MYC gene amplification is often acquired in lethal distant breast cancer metastases of unamplified primary tumors.

In breast cancer, amplification of MYC is consistently observed in aggressive forms of disease and correlates with poor prognosis and distant metastases. However, to date, a systematic analysis of MYC amplification in metastatic breast cancers has not been reported. Specifically, whether the MYC amplification status may change in metastases in comparison to the corresponding primary breast tumor, and potential variability among different metastases within the same patient have also not been assessed. We generated single patient tissue microarrays consisting of both primary breast carcinomas and multiple matched systemic metastases from 15 patients through our previously described rapid autopsy program. In total, the 15 tissue microarrays contained 145 primary tumor spots and 778 spots derived from 180 different metastases. In addition, two separate tissue microarrays were constructed composed of 10 matched primary breast cancers and corresponding solitary metastases sampled not at autopsy but rather in routine surgical resections. These two tissue microarrays totaled 50 primary tumor spots and 86 metastatic tumor spots. For each case, hormone receptor status, HER2/neu, EGFR and CK5/6 expression were assessed, and the cases were characterized as luminal, basal-like or HER2 based on published criteria. Both fluorescence in situ hybridization and immunohistochemistry for MYC was performed on all cases. Of the 25 cases, 24 were evaluable. While 4 of 24 primary tumors (16%) demonstrated MYC amplification, an additional 6 (25% of total evaluable cases) acquired MYC amplification in their systemic metastases. Of note, there was remarkably little heterogeneity in MYC copy number among different metastases from the same patient. MYC immunoreactivity was increased in metastases relative to matched primaries in the surgical cohort, although there was no perfect correlation with MYC amplification. In conclusion, amplification of MYC is a frequent event in breast cancer, but occurs more frequently as a diffuse, acquired event in metastatic disease than in the corresponding primary. These observations underscore the importance of MYC in breast cancer progression/metastasis, as well as its relevance as a potential therapeutic target in otherwise incurable metastatic disease.

Relationship between molecular subtype of invasive breast carcinoma and expression of gross cystic disease fluid protein 15 and mammaglobin.

We investigated the expression of gross cystic disease fluid protein 15 (GCDFP) and mammaglobin (MGB) by immunohistochemical analysis in 71 invasive breast carcinomas (IBCs) subtyped into luminal (A and B), HER2, basal-like carcinoma (BLC), and unclassified triple-negative carcinoma (UTNC) by established surrogate immunohistochemical profiles. GCDFP and MGB were less likely to be expressed in BLC than in HER2 cancers (P = .000021 and P = .013, respectively) or luminal cancers (P = .00002 and P = .00008, respectively). However, the difference in GCDFP or MGB expression between HER2 and luminal cancers was not significant (P = 1.0 and P = .671, respectively). Our results suggest that luminal cancers demonstrate similar degrees of apocrine differentiation as HER2 cancers. Most BLCs and UTNCs are negative for MGB and GCDFP. Correlation with clinical findings may be needed to exclude the possibility of a metastasis to the breast when BLCs or UTNCs are encountered in a limited sample such as a core biopsy sample.

Incidental minimal atypical lobular hyperplasia on core needle biopsy: correlation with findings on follow-up excision.

INTRODUCTION: Atypical lobular hyperplasia (ALH), often an incidental finding in breast core biopsies, is largely considered to be a risk factor for carcinoma rather than a direct precursor. However, management of ALH is controversial. We review our experience with incidental minimal ALH on core biopsy, and correlate with excision and follow-up results. DESIGN: We evaluated all cases of ALH on core biopsy from 1999 to 2009 from our institution, focusing on cases with < or =3 foci of ALH (minimal), paired excision, and no other lesion on the core biopsy that by itself would require excision. Cases with discordant clinical/radiologic impressions, suggesting that a suspicious lesion had been missed on biopsy, were excluded. Therefore, the excisions were performed because of the diagnosis of ALH. RESULTS: Of 56 cases with ALH on biopsy and paired excision, 42 showed minimal ALH. On excision, 26 had residual ALH and 13 were benign. Three cases had other atypical lesions: lobular carcinoma in situ (2 cases) and mild atypical ductal hyperplasia separate from the biopsy site (1 case). On follow-up, only 1 patient developed subsequent ALH in the same breast. No other ipsilateral lesions were later diagnosed (mean follow-up 3.2 y). CONCLUSIONS: No case with ALH on biopsy had a lesion on excision requiring further treatment, suggesting that these patients can be managed more conservatively. Furthermore, no patients were diagnosed with a higher grade lesion in the same breast on follow-up. We propose that, if there is close radiologic correlation and follow-up, minimal incidental ALH on core biopsy (< or =3 foci) does not require excision.

Heterogeneity of Bcl-2 expression in metastatic breast carcinoma.

Bcl-2 is an antiapoptotic protein that promotes cell survival, but also may block proliferation. In breast cancer, bcl-2 expression correlates with favorable prognosis and estrogen receptor (ER) positivity. However, experimental data have paradoxically suggested that bcl-2 promotes chemoresistance and metastasis. A direct and comprehensive comparison of bcl-2 expression between primary breast carcinomas and paired distant metastases has not been performed. We completed rapid autopsies on 17 patients with archived primary tumors and metastatic breast carcinoma, and created single-patient tissue microarrays containing each patient's primary tumor and matched metastases. Expression of bcl-2, ER, progesterone receptor, and HER-2 in primary tumors and matched metastases were compared by immunohistochemistry. All 11 ER-positive cases showed bcl-2 labeling in the primary tumor, whereas only 3 of 6 ER-negative cases did (P=0.029). In 10 cases, bcl-2 labeling in metastases was similar to that of the primary, although 3 cases showed significant variation among metastases. In six other cases, bcl-2 labeling was lost or significantly diminished in metastases. Five of the latter cases were Luminal A (ER-positive, HER-2-negative) primaries, three of which lost hormone receptors in metastases. Only 1 of 17 cases showed an increase in bcl-2 labeling in metastases compared with the paired primary tumor. In conclusion, bcl-2 is infrequently upregulated in metastatic breast carcinoma. Instead, downregulation of bcl-2 expression may occur in the setting of hormone therapy resistance. Our findings call into question the potential utility of anti-bcl-2 therapy in metastatic breast cancer.

Pathologic complete response to preoperative sequential doxorubicin/cyclophosphamide and single-agent taxane with or without trastuzumab in stage II/III HER2-positive breast cancer.

BACKGROUND: Four major clinical trials have established that trastuzumab added to adjuvant systemic chemotherapy for women with HER2+ breast cancer significantly improves disease-free and overall survival compared with chemotherapy alone. We evaluated pathologic complete response (pCR) rate and cardiac safety of preoperative doxorubicin and cyclophosphamide followed by a taxane with or without trastuzumab. PATIENTS AND METHODS: We reviewed pCR rate and change in left ventricular ejection fraction in women with operable HER2+ breast cancer (defined as immunohistochemical 3+ or fluorescence in situ hybridization ratio > or = 2.2) who were treated between 2002 and 2008 with doxorubicin and cyclophosphamide followed by a taxane with or without trastuzumab before definitive breast surgery. RESULTS: We identified 33 patients, of whom 42.4% received preoperative chemotherapy without trastuzumab and 57.6% of whom received trastuzumab with chemotherapy. The pCR rates were 28.6% and 52.6% in the group that received chemotherapy alone or with trastuzumab, respectively (odds ratio, 2.78; 95% CI, 0.64-12.1; P = .173). Severe cardiac events or treatment delays as a result of cardiac toxicity were not observed. With a median follow-up time of 14 months, 21.4% of patients in the non-trastuzumab group and 10.5% in the trastuzumab group had disease recurrence. CONCLUSION: Sequential administration of preoperative doxorubicin and cyclophosphamide followed by a taxane and trastuzumab combination is safe in women with primary operable HER2+ breast cancer and is associated with a high pCR rate. Large randomized phase III clinical trials are evaluating the role of preoperative trastuzumab when added to anthracycline- and/or taxane-based regimens.

Pseudoangiomatous stromal hyperplasia (PASH) of the breast with foci of morphologic malignancy: a case of PASH with malignant transformation?

Pseudoangiomatous stromal hyperplasia (PASH) is a benign proliferation of the hormonally responsive, specialized mammary stroma characterized by slit-like pseudovascular spaces lined by bland spindle cells. It is usually an incidental microscopic finding but in some cases it may present as a slowly growing mass. A malignant counterpart for this lesion has not been reported. We describe a case of PASH with foci of malignant histologic features presenting as a slowly growing mass in a 30-year-old woman. The previously reported variants of PASH and the other mammary stromal lesions related to PASH are also discussed. This is perhaps the first case of PASH with foci of malignant histologic features reported in the literature and represents a rare sarcoma derived from specialized hormonally responsive mammary stroma.

The alternative lengthening of telomeres phenotype in breast carcinoma is associated with HER-2 overexpression.

Approximately 10-15% of human cancers do not show evidence of telomerase activity, and a subset of these maintain telomere lengths by a recombination-based mechanism termed alternative lengthening of telomeres (ALT). The ALT phenotype, relatively common in certain sarcomas and germ cell tumors, is very rare in carcinomas. In this study we describe evidence for the ALT phenotype in molecular subclasses of breast carcinoma, specifically a subset of cancers with HER-2 overexpression. Tissue microarrays were created from 71 invasive ductal carcinomas of the breast categorized into subclasses, and telomere lengths were directly assessed using fluorescence in situ hybridization with combined promyelocytic leukemia (PML) protein immunofluorescence. The ALT phenotype was identified in 3 of 21 HER-2-positive cases, but in none of the other 50 cases (P=0.023). This is the first direct observation of this mechanism of telomere maintenance in breast carcinoma unrelated to Li-Fraumeni syndrome. The correlation of the ALT phenotype with HER-2 positivity, both of which involve abnormal DNA amplification, suggests a possible common underlying mechanism. This telomere phenotype confers a poor prognosis in some cancers; two of the three cases in our study showed rapid tumor progression, possibly suggesting that it may adversely affect outcome in breast carcinoma as well. As cancers using the ALT pathway are predicted to be resistant to therapies based on telomerase inhibition, these results may have therapeutic consequences.

Ductal carcinoma in situ in African American versus Caucasian American women: analysis of clinicopathologic features and outcome.

BACKGROUND: Invasive breast carcinoma has a more aggressive phenotype and a higher mortality rate in African American (AA) than in Caucasian American (CA) women. The characteristics of ductal carcinoma in situ (DCIS) in the AA population have not been extensively studied. METHODS: The authors reviewed cases of DCIS diagnosed in AA and CA patients between 1996 and 2000 at their institution. Treatment and outcome were obtained from the clinical charts and the Surveillance, Epidemiology, and End Results database. They identified 217 AA (61%) and 141 CA (39%) patients. RESULTS: AA women were significantly older at diagnosis (61 years vs 56 years, P = .001), and the size of the tumor was larger in AA patients (P = .001). The other pathological features examined were not statistically different between the 2 groups. Treatments with surgery and radiation were also similar. However, the CA patients were more likely to receive hormone therapy. Recurrence rate as DCIS or invasive carcinoma was similar in both patient groups, as was death due to disease. Time to recurrence with invasive carcinoma, however, was shorter for AA patients (32.8 +/- 13 vs 58 +/- 9; P = .02). Only overall survival (OS) rate was higher for CA patients (92% vs 71% at 10 years; P = .003). CONCLUSIONS: Unlike invasive carcinoma, DCIS is diagnosed at a later age in AA patients. Except for larger size, DCIS does not have a more aggressive histology in AA patients. Treatment and recurrence rate were similar in both groups, as was death due to breast cancer. OS, however, was worse in AA women.

Most basal-like breast carcinomas demonstrate the same Rb-/p16+ immunophenotype as the HPV-related poorly differentiated squamous cell carcinomas which they resemble morphologically.

Basal-like carcinomas (BLCs) of the breast share discriminatory morphologic features with poorly differentiated high-risk human papilloma virus (HPV)-related squamous cell carcinomas of the oropharynx, penis, and vulva. Because HPV E7 protein inactivates the retinoblastoma (Rb) protein, diffuse p16 expression is a surrogate marker for these high-risk HPV-related carcinomas. HPV E6 protein also inactivates p53, further compromising the G1-S cell cycle checkpoint. The Rb/p16/p53 immunohistochemical profile of BLC of the breast has not been well characterized. Tissue microarrays containing 71 invasive ductal carcinomas (IDCs) of the breast were immunolabeled for p16, Rb, p53, and Ki-67. The cases included 4 distinct groups of IDCs having surrogate immunohistochemical profiles corresponding to categories defined by gene expression profiling (17 luminal A, 7 luminal B, 14 HER-2+, and 21 BLC), along with 12 unclassifiable triple negative carcinomas (UTNCs). Twenty-five of the 71 IDC were Rb negative/p16 diffuse positive (Rb-/p16+). These included 15 of 21 BLC and 9 of 12 UTNC, but only 1 of 14 HER-2 positive cases and none of the 17 luminal A or 7 luminal B cases (P<0.01, BLC or UTNC vs. others). Six of the Rb-/p16+ IDC also had a significant ductal carcinoma in situ component. The ductal carcinoma in situ in 4 of these 6 cases showed the same Rb-/p16+ phenotype as the associated IDC. BLC and UTNC had the highest Ki-67 indices of the 5 groups, even when matched for grade. The Rb-/p16+ phenotype and the Rb-/p16+/p53 overexpressing phenotype correlated with increased proliferation within the BLC group. In conclusion, BLC and UTNC, but not HER-2, luminal A, or luminal B carcinomas, frequently demonstrate an Rb-/p16+ phenotype, similar to the HPV-related squamous cell carcinomas that BLC resemble morphologically. This subset may represent a more homogenous group than BLC as defined currently.

Serial analysis of gene expression of lobular carcinoma in situ identifies down regulation of claudin 4 and overexpression of matrix metalloproteinase 9.

INTRODUCTION: Although lobular carcinoma in situ (LCIS) has traditionally been viewed as a marker of breast cancer risk, recent clinical, pathological and genetic analyses have supported the concept that LCIS is a low risk, direct precursor of invasive lobular carcinoma. Global gene expression profiling of LCIS has not been performed. METHODS: We analysed the comprehensive gene expression profile of a unique case of mass-forming LCIS using serial analysis of gene expression (SAGE). This SAGE library is publicly available online. By comparing the gene expression profile of LCIS to that of benign breast epithelium and stroma, we identified several genes up and down regulated in LCIS. Differential expression of selected genes not previously studied in LCIS was validated at the protein level by immunohistochemistry and at the RNA level by quantitative reverse transcriptase PCR (RT-PCR). RESULTS: We identified down regulation of claudin 4 and overexpression of matrix metalloproteinase 9 in LCIS relative to normal breast epithelium and stroma. We validated these findings by immunohistochemistry in a separate series of 11 and 19 LCIS cases, respectively. Overexpression of matrix metalloproteinase 9 was further confirmed by quantitative RT-PCR analysis of the index case. CONCLUSIONS: We have created the first global gene expression profile of LCIS, and demonstrated down regulation of cell junction proteins (an expected result) and overexpression of matrix metalloproteinase 9 (an unexpected result). Additional analysis of this data made available as an online resource should facilitate further molecular characterisation of LCIS.

Comedo-ductal carcinoma in situ: A paradoxical role for programmed cell death.

Comedo-DCIS is a histologic subtype of preinvasive breast neoplasia that is characterized by prominent apoptotic cell death and has greater malignant potential than other DCIS subtypes. We investigated the mechanisms of apoptosis in comedo-DCIS and its role in conversion of comedo-DCIS to invasive cancer. Clinical comedo-DCIS excisions and the MCF10DCIS.com human breast cancer model which produces lesions resembling comedo-DCIS were analyzed. Apoptotic luminal and myoepithelial cells were identified by TUNEL and reactivity to cleaved PARP antibody and cell death assessed by Western blotting, Mitocapture and immunohistochemical assays. MCF10DCIS.com cells undergo spontaneous apoptosis in vitro, both in monolayers and multicellular spheroids; it is associated with increased mitochondrial membrane permeability, increase in Bax/Bcl-2 ratio and occurs via caspase-9-dependent p53-independent pathway. This suggests that apoptosis is stromal-independent and that the cells are programmed to undergo apoptosis. Immunostaining with cleaved PARP antibody showed that myoepithelial apoptosis occurs before lesions progress to comedo-DCIS in both clinical comedo-DCIS and in vivo MCF10DCIS.com lesions. Intense staining for MMP-2, MMP-3, MMP-9 and MMP-11 was observed in the stroma and epithelia of solid DCIS lesions prior to conversion to comedo-DCIS in clinical and MCF10DCIS.com lesions. Gelatin zymography showed higher MMP-2 levels in lysates and conditioned media of MCF10DCIS. com cells undergoing apoptosis. These data suggest that signals arising from the outside (microenvironmental) and inside (internal genetic alterations) of the duct act in concert to trigger apoptosis of myoepithelial and luminal epithelial cells. Our findings implicate spontaneous apoptosis in both the etiology and progression of comedo-DCIS. It is possible that spontaneous apoptosis facilitates elimination of cells thus permitting expansion and malignant transformation of cancer cells that are resistant to spontaneous apoptosis.

Hu/Mu ProtIn oligonucleotide microarray: dual-species array for profiling protease and protease inhibitor gene expression in tumors and their microenvironment.

Proteolysis is a critical regulatory mechanism for a wide variety of physiologic and pathologic processes. To assist in the identification of proteases, their endogenous inhibitors, and proteins that interact with proteases or proteolytic pathways in biological tissues, a dual-species oligonucleotide microarray has been developed in conjunction with Affymetrix. The Hu/Mu ProtIn microarray contains 516 and 456 probe sets that survey human and mouse genes of interest (proteases, protease inhibitors, or interactors), respectively. To investigate the performance of the array, gene expression profiles were analyzed in pure mouse and human samples (reference RNA; normal and tumor cell lines/tissues) and orthotopically implanted xenografts of human A549 lung and MDA-MB-231 breast carcinomas. Relative gene expression and "present-call" P values were determined for each probe set using dChip and MAS5 software, respectively. Despite the high level of sequence identity of mouse and human protease/inhibitor orthologues and the theoretical potential for cross-hybridization of some of the probes, >95% of the "present calls" (P<0.01) resulted from same-species hybridizations (e.g., human transcripts to human probe sets). To further assess the performance of the microarray, differential gene expression and false discovery rate analyses were carried out on human or mouse sample groups, and data processing methods to optimize performance of the mouse and human probe sets were identified. The Hu/Mu ProtIn microarray is a valuable discovery tool for the identification of components of human and murine proteolytic pathways in health and disease and has particular utility in the determination of cellular origins of proteases and protease inhibitors in xenograft models of human cancer.

Aberrant expression of X-linked genes RbAp46, Rsk4, and Cldn2 in breast cancer.

The consequence of activation status or gain/loss of an X-chromosome in terms of the expression of tumor suppressor genes or oncogenes in breast cancer has not been clearly addressed. In this study, we investigated the activation status of the X-chromosomes in a panel of human breast cancer cell lines, human breast carcinoma, and adjacent mammary tissues and a panel of murine mammary epithelial sublines ranging from low to high invasive potentials. Results show that most human breast cancer cell lines were homozygous, but both benign cell lines were heterozygous for highly polymorphic X-loci (IDS and G6PD). On the other hand, 60% of human breast carcinoma cases were heterozygous for either IDS or G6PD markers. Investigation of the activation status of heterozygous cell lines revealed the presence of only one active X-chromosome, whereas most heterozygous human breast carcinoma cases had two active X-chromosomes. Furthermore, we determined whether or not an additional active X-chromosome affects expression levels of tumor suppressor genes and oncogenes. Reverse transcription-PCR data show high expression of putative tumor suppressor genes Rsk4 and RbAp46 in 47% and 79% of breast carcinoma cases, respectively, whereas Cldn2 was down-regulated in 52% of breast cancer cases compared with normal adjacent tissues. Consistent with mRNA expression, immunostaining for these proteins also showed a similar pattern. In conclusion, our data suggest that high expression of RbAp46 is likely to have a role in the development or progression of human breast cancer. The activation status of the X-chromosome may influence the expression levels of X-linked oncogenes or tumor suppressor genes.

The major autopsy findings in adult patients after hematopoietic stem cell transplantation.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) is a curative treatment option for hematological malignancies, but this treatment can be associated with a mortality risk. MATERIAL/METHODS: A ten-year retrospective review of all autopsies was performed where those who underwent HSCT were studied. The major autopsy findings and the cause of death were characterized and compared between those seen in allogeneic and those in autologous HSCT recipients. The study period preceded the use of prophylactic antifungal agents. RESULTS: A total of 66 autopsies were identified; 52 (79%) received allogeneic and 14 (21%) autologous transplantation. Death occurred at a median of 85 days post transplantation (range 2-1825 days); 36 (55%) died within the first 100 days post stem cells infusion. The major complications for HSCT patients were pulmonary, including diffuse alveolar damage (DAD), acute pneumonia and invasive pulmonary aspergillosis. The most common cause of death in the allogeneic HSCT group was DAD (13/52; 25%), followed by invasive pulmonary aspergillosis (10/52; 19%), acute pneumonia (10/52; 19%) and massive gastrointestinal bleeding (6/52; 12%); in the autologous group causes were disease relapse/progression of the underlying malignancy (4/14; 29%), acute pneumonia (3/14; 21%) and DAD (2/14; 14%). CONCLUSIONS: We conclude that the spectrum of disease entities, commonly diagnosed at autopsy in HSCT recipients may provide insight to clinicians for anticipating complications and consequently help in the management of these high risk patients. The increased infectious complications observed in the allogeneic transplant cases may be explained by immunosuppression and that the study period preceded the use of prophylactic antifungal agents. However, relapse/progression of the disease is the predominant cause of mortality after autologous transplant.

Clinicopathologic analysis of solid papillary carcinoma of the breast and associated invasive carcinomas.

Solid papillary carcinomas (SPCs) are uncommon tumors composed of circumscribed large cellular nodules separated by bands of dense fibrosis. The aim of this study was to further elucidate the characteristics of SPC, the types and significance of invasive carcinomas associated with these tumors, and the long-term clinical outcome. Fifty-eight SPCs were analyzed (mean follow-up, 9.4 years). Cases were divided into three groups: 1) SPC only (32.7%), 2) SPC with extravasated mucin (8.6%), and 3) SPC with invasive components (58.7%) consisting of neuroendocrine-like (29.5%), colloid (23.5%), ductal not otherwise specified (14.5%), lobular (3%), tubular (3%), or mixed (26.5%). The mean age was 72 years. All were estrogen receptor positive and 86% were histologic grade 1. The total size of the tumor measured 0.3 to 15 cm. In the group with invasive carcinoma, the size of invasion was 0.1 to 4 cm. Axillary nodes were involved in 13% of the cases (6 of 46); all of these had an invasive component in the primary tumor. Local recurrence was seen in 5 patients, all from the group with invasive carcinoma. Overall, 11.7% died of their tumor, 1 to 4 years after diagnosis (mean, 2.3 years); none of them belongs to the group of noninvasive SPC. Five of the 6 patients who died of tumor had invasive components. The sixth patient who died with "metastatic signet-ring cell carcinoma" at 10 years was in the group of patients with SPC with extravasated mucin where the SPC lesion had prominent signet-ring cell features. In conclusion, SPCs are heterogeneous lesions that arise in older women and have an indolent behavior. Lymph node and distant metastases are uncommon and generally limited to cases with (conventional) invasive components.

High-grade neuroendocrine carcinoma of the ampulla of vater: a clinicopathologic and immunohistochemical analysis of 14 cases.

We describe the clinical and pathologic features of 14 cases of high-grade neuroendocrine carcinoma (HGNEC) of the ampulla of Vater classified according to WHO classification of lung tumors into small cell carcinoma (SCC, 6 cases) and large cell neuroendocrine carcinoma (LCNEC, 8 cases) types. The immunohistochemical findings were compared with those of 13 cases of primary poorly differentiated ampullary adenocarcinomas (PDACA) lacking neuroendocrine morphology. The mean age of 10 males and 4 females was 70 years. The mean tumor size was 2.5 cm. Ten of 13 patients had lymph node metastases (mean, 2.3 nodes involved). Documented sites of distant metastases included brain and liver. Overall, 64% of patients with ampullary HGNEC died of disease (mean follow-up, 14.5 months). Four patients had no evidence of disease after resection (mean, 20 months). Half of the tumors were associated with adenomas of the adjacent mucosa, 2 with high-grade dysplasia. Two HGNECs were combined with a conventional adenocarcinoma and another with a squamous cell carcinoma component. By immunohistochemistry, the HGNECs were positive for cytokeratins (AE1/AE3, 100%; Cam5.2, 67%; CK7, 87%; CK20, 38%), similar to the pattern found in PDACAs. p27 expression was lost in 1 case of HGNEC and in all PDACAs. Retinoblastoma (Rb) protein expression was lost in 60% of HGNECs and in none of the PDACA cases. In conclusion, HGNECs of the ampulla are rare (2%-3% of ampullary tumors in our material). The clinical course parallels that of their pulmonary counterparts and appears to be worse than that of locally advanced ampullary adenocarcinomas. The association with adenoma and or conventional adenocarcinoma components may suggest a common pathway in the initial carcinogenesis of these two types of tumors. Loss of Rb expression, a characteristic finding in pulmonary SCCs, is present in almost half of ampullary HGNECs. In contrast, p27 expression is lost in PDACAs and retained in most HGNECs. Thus, there are differences in the molecular phenotypes of these two types of ampullary carcinoma, supporting the distinction of poorly differentiated carcinomas with a neuroendocrine phenotype from those without.

Carcinomas with micropapillary morphology: clinical significance and current concepts.

Invasive micropapillary carcinoma has been recently recognized as a rare but distinctive variant of carcinoma in various anatomic sites, including breast, urinary bladder, lung, and major salivary glands. Morphologically, it is characterized by small tight clusters of neoplastic cells floating in clear spaces resembling lymphatic channels. Most often this growth pattern is mixed with a variable component of conventional carcinoma or other variants. In addition to a unique morphology, tumors with invasive micropapillary growth share a high propensity for lymphovascular invasion and lymph node metastases. Patients have typically high-stage disease at presentation and a poor clinical outcome compared with that of patients with conventional carcinoma arising in the same organ site. In this article the author reviews the available literature on tumors displaying a micropapillary component.

Pathogenesis of invasive micropapillary carcinoma: role of MUC1 glycoprotein.

Invasive micropapillary carcinoma, a tumor with highly infiltrative characteristics is defined by a distinctive cleft formation around the neoplastic cell clusters which is presumably a result of the detachment of the cells from the stroma due to as yet undetermined factors. Ultrastructural examination performed on a handful of cases demonstrated an unexpected secretory activity in the stroma-facing surface of the cells. MUC1 is a glycoprotein typically expressed in the apical surface of normal epithelial cells, responsible for maintaining lumen formation. In conventional adenocarcinomas, MUC1 expression is largely intracytoplasmic, intercellular, or apical (in glandular areas). The MUC1 expression pattern was investigated by immunohistochemical staining in invasive micropapillary carcinoma of breast (n=11), pancreas (n=5), gynecologic tract (n=11) and urinary bladder (n=10). The results were contrasted with the staining pattern in conventional carcinomas of the same organs (n=202). In all invasive micropapillary carcinoma, MUC1 expression was predominantly in the stroma-facing surface of the cell clusters (basal), accentuating the outlines of the micropapillary units by forming a distinct band on this surface. In conventional carcinoma the labeling was mostly apical in areas with lumen formation and intracytoplasmic and intercellular in the poorly differentiated areas. In conclusion, in the micropapillary pattern of invasive carcinoma, the expression of MUC1, is largely limited to the basal surface of the cells in contrast to conventional carcinomas in which MUC1 is largely apical, intracytoplasmic or intercellular. This provides support for the reversal of cell orientation as an important factor of the morphogenesis and possibly the pathogenesis of invasive micropapillary carcinoma. Since MUC1 is known to have a role in lumen formation, and has an inhibitory role in the cell to stroma interaction, it is conceivable that it is a key factor in the detachment of cells from stroma allowing for the dissection of the connective tissue and easing the spread of cells.

Secondary tumors of the pancreas: an analysis of a surgical and autopsy database and review of the literature.

The vast majority of pancreatic carcinomas are primary, and, among these, more than 90% are of ductal origin. However, a variety of extrapancreatic tumors may involve the pancreas secondarily and may manifest different clinicopathological characteristics and outcomes. In this study, pathology material from 973 surgical specimens and 4955 adult autopsy cases was reviewed to identify the tumors metastatic to or secondarily involving the pancreas. Biliary and periampullary neoplasms and tumors confined to peripancreatic soft tissue were excluded. In the autopsy series, the pancreas was involved by tumor in 190 cases, and 81 of these were secondary tumors. These were predominantly of epithelial origin, most commonly from lung (34), followed by GI tract (20), kidney (4), breast (3), liver (2), ovary (1), and urinary bladder (1). In addition, there were six tumors of hematopoietic origin, two melanomas, two sarcomas, and two mesotheliomas. Among the 973 surgical specimens, 38 cases contained metastatic tumors to the pancreas. Of these, 11 were lymphomas, and the others were carcinomas of stomach (7), kidney (6), lung (2), liver, prostate, ovary, uterus (1 case of each), and a Merkel cell carcinoma. In addition, there were three malignant gastrointestinal stromal tumors and one retroperitoneal leiomyosarcoma. In conclusion, lung cancer is the most common source of metastasis to pancreas, followed by gastrointestinal carcinomas and lymphomas. These tumors are usually seen in patients with disseminated disease and are detected mainly in autopsies. Secondary tumors constitute about 4% of pancreatic specimens in the authors' surgical database. Approximately one-third of them are clinically mistaken as primary tumors of the pancreas. These are predominantly hematopoietic malignancies or carcinomas of renal or gastric origin. Secondary tumors should be entertained in both the clinical and pathological differential diagnosis of pancreatic neoplasia.

Pathogenesis of colloid (pure mucinous) carcinoma of exocrine organs: Coupling of gel-forming mucin (MUC2) production with altered cell polarity and abnormal cell-stroma interaction may be the key factor in the morphogenesis and indolent behavior of colloid carcinoma in the breast and pancreas.

In the exocrine organs, breast and pancreas, colloid carcinoma (CC, pure mucinous carcinoma), characterized by well-circumscribed lakes of mucin that contain scanty, detached malignant cells, has a significantly better prognosis than conventional ductal carcinomas (DCs). It has been speculated by us and others that an inverse polarization of cells may be responsible for the accumulation of extracellular mucin. Another possibility is that this mucin is biochemically and biologically distinct from the mucin secreted by the conventional carcinomas of these organs. This study was undertaken to investigate these two hypotheses: 1) To test whether there is indeed an alteration in cell polarity in CC. Immunohistochemical stains for luminal surface glycoproteins (carcinoembryonic antigen in pancreas and MUC1 in breast) were performed in 18 pancreatic and 30 mammary CCs and compared with the expression pattern in DCs (37 pancreatic and 47 mammary) and normal ducts. The results disclosed that these glycoproteins were expressed predominantly in the stroma-facing surfaces of CC cells, in contrast to the DCs, in which the expression was either on the luminal surface (in well-differentiated areas) or dispersed throughout the cell, intracytoplasmic in the poorly differentiated areas. Ultrastructural examination performed on 10 breast and two pancreatic CCs showed the condensation of mucigen granules (generally underlying an apical-type cell membrane) in the stroma-facing surface in all cases. In contrast, in the DCs (five pancreatic and five mammary), no clustering of mucigen granules was identified in the cytoplasm facing the stroma in any of the cases. Furthermore, no external lamina or basement membrane was detected in any of the CCs, whereas in the DCs, a distinct (in 3 of 10) or discontinuous (4 of 10) external lamina separated the tumor cells from the stroma. 2) To determine the expression frequency of MUC2 in CCs and to compare it with that in DCs and normal tissue, immunohistochemical stains with MUC2 (clone ccp58) were performed. MUC2 expression was detected in 18 of 18 pancreatic and 30 of 30 breast CCs and was exceedingly rare in DCs (1 of 136 pancreatic DC and 3 of 47 mammary, p <0.0001 in both organs). No labeling was detected in normal ducts. In conclusion, it appears that coupling of two factors is important for the distinctive morphologic characteristics and slow growth of CCs: The first one is the alteration in cell orientation as evidenced by the direction of surface glycoproteins and secretory organelles to the stroma-facing surface of the cells and the disruption of cell-stroma interaction as manifested by lack of basal lamina formation. Apparently, this altered polarity allows the CC cells to secrete the mucin toward the stroma. The mucin produced, MUC2 (also called gel-forming mucin), is highly specific for CC and is known to form strong bonds with the stroma, and also was found recently to have tumor suppressor activity. This distinctive mucin, accumulated in the stroma surrounding the CC cells, may act as a containing factor, slackening the spread of the cells.