Neuroendocrine small cell carcinoma of the cervix: A case report.

Merkel cell polyomavirus (MCPyV) has been found in patients with Merkel cell carcinoma and respiratory tract infections. Merkel cell carcinoma is a primary aggressive neuroendocrine carcinoma of the skin. It has been demonstrated that MCPyV can be transmitted during sexual activity and may be present in the oral and anogenital mucosa. The aim of the present study was to evaluate whether MCPyV coexisted with HPV in three cases of neuroendocrine small cell carcinoma of the cervix using PCR and immunohistochemical analysis Three cases of NSC of the cervix were identified in the pathology archives of Parma University (Italy). Of these, two cases were associated with an adenocarcinomatous component. A set of general primers from the L1 region (forward, L1C1 and reverse, L1C2 or L1C2M) was PCR amplified to detect the broad-spectrum DNA of genital HPV. The presence of MCPyV was investigated via immunohistochemistry using a mouse monoclonal antibody against the MCPyV LT antigen and through PCR analysis to separate viral DNA. HPV DNA was present in all three neuroendocrine carcinomas and in the adenocarcinoma component of the two mixed cases. None of the cases were immunoreactive to CM2B4 and did not contain viral DNA in either their neuroendocrine or adenocarcinomatous component. Whilst it is difficult to draw definitive conclusions from such a small sample size, these data suggested that MCPyV does not coexist with HPV in the cervix. However, in the present study, the absence of detectable MCPyV may have been due to the presence of a genotype that was not detected by the primers used in the PCR analysis or by the antibody used for the immunohistochemical study. MCPyV microRNA may also have been present, inhibiting LT expression. Additional studies with larger cohorts and more advanced molecular biology techniques are required to confirm the hypothesis of the current study.

In Vitro and In Vivo Anti-Candida Activity and Structural Analysis of Killer Peptide (KP)-Derivatives.

The previously described decapeptide AKVTMTCSAS (killer peptide, KP), derived from the variable region of a recombinant yeast killer toxin-like anti-idiotypic antibody, proved to exert a variety of antimicrobial, antiviral, and immunomodulatory activities. It also showed a peculiar self-assembly ability, likely responsible for the therapeutic effect in animal models of systemic and mucosal candidiasis. The present study analyzed the biological and structural properties of peptides derived from KP by substitution or deletion of the first residue, leaving unchanged the remaining amino acids. The investigated peptides proved to exert differential in vitro and/or in vivo anti-Candida activity without showing toxic effects on mammalian cells. The change of the first residue in KP amino acidic sequence affected the conformation of the resulting peptides in solution, as assessed by circular dichroism spectroscopy. KP-derivatives, except one, were able to induce apoptosis in yeast cells, like KP itself. ROS production and changes in mitochondrial transmembrane potential were also observed. Confocal and transmission electron microscopy studies allowed to establish that selected peptides could penetrate within C. albicans cells and cause gross morphological alterations. Overall, the physical and chemical properties of the first residue were found to be important for peptide conformation, candidacidal activity and possible mechanism of action. Small antimicrobial peptides could be exploited for the development of a new generation of antifungal drugs, given their relative low cost and ease of production as well as the possibility of devising novel delivery systems.

A Peptide Found in Human Serum, Derived from the C-Terminus of Albumin, Shows Antifungal Activity In Vitro and In Vivo.

The growing problem of antimicrobial resistance highlights the need for alternative strategies to combat infections. From this perspective, there is a considerable interest in natural molecules obtained from different sources, which are shown to be active against microorganisms, either alone or in association with conventional drugs. In this paper, peptides with the same sequence of fragments, found in human serum, derived from physiological proteins, were evaluated for their antifungal activity. A 13-residue peptide, representing the 597-609 fragment within the albumin C-terminus, was proved to exert a fungicidal activity in vitro against pathogenic yeasts and a therapeutic effect in vivo in the experimental model of candidal infection in Galleria mellonella. Studies by confocal microscopy and transmission and scanning electron microscopy demonstrated that the peptide penetrates and accumulates in Candida albicans cells, causing gross morphological alterations in cellular structure. These findings add albumin to the group of proteins, which already includes hemoglobin and antibodies, that could give rise to cryptic antimicrobial fragments, and could suggest their role in anti-infective homeostasis. The study of bioactive fragments from serum proteins could open interesting perspectives for the development of new antimicrobial molecules derived by natural sources.

Novel Activity of a Synthetic Decapeptide Against Toxoplasma gondii Tachyzoites.

The killer peptide KP is a synthetic decapeptide derived from the sequence of the variable region of a recombinant yeast killer toxin-like microbicidal single-chain antibody. KP proved to exert significant activities against diverse microbial and viral pathogens through different mechanisms of action, but little is known of its effect on apicomplexan protozoa. The aim of the present study was to evaluate the in vitro activity of KP against Toxoplasma gondii, a globally widespread protozoan parasite of great medical interest. The effect of KP treatment and its potential mechanism of action on T. gondii were evaluated by various methods, including light microscopy, quantitative PCR, flow cytometry, confocal microscopy, and transmission electron microscopy. In the presence of KP, the number of T. gondii tachyzoites able to invade Vero cells and the parasite intracellular proliferation were significantly reduced. Morphological observation and analysis of apoptotic markers suggested that KP is able to trigger an apoptosis-like cell death in T. gondii. Overall, our results indicate that KP could be a promising candidate for the development of new anti-Toxoplasma drugs with a novel mechanism of action.

Fungicidal activity of peptides encoded by immunoglobulin genes.

Evidence from previous works disclosed the antimicrobial, antiviral, anti-tumour and/or immunomodulatory activity exerted, through different mechanisms of action, by peptides expressed in the complementarity-determining regions or even in the constant region of antibodies, independently from their specificity and isotype. Presently, we report the selection, from available databases, of peptide sequences encoded by immunoglobulin genes for the evaluation of their potential biological activities. Synthetic peptides representing the translated products of J lambda and J heavy genes proved to act in vitro against pathogenic fungi, entering yeast cells and causing their death, and exerted a therapeutic effect in a Galleria mellonella model of infection by Candida albicans. No haemolytic, cytotoxic and genotoxic effects were observed on mammalian cells. These findings raise the hypothesis that antibodies could be the evolutionary result of the adaptive combination of gene products ancestrally devoted to innate antimicrobial immunity.

Dissecting the Structure-Function Relationship of a Fungicidal Peptide Derived from the Constant Region of Human Immunoglobulins.

Synthetic peptides encompassing sequences related to the complementarity-determining regions of antibodies or derived from their constant region (Fc peptides) were proven to exert differential antimicrobial, antiviral, antitumor, and/or immunomodulatory activitiesin vitroand/orin vivo, regardless of the specificity and isotype of the parental antibody. Alanine substitution derivatives of these peptides exhibited unaltered, increased, or decreased candidacidal activitiesin vitro The bioactive IgG-derived Fc N10K peptide (NQVSLTCLVK) spontaneously self-assembles, a feature previously recognized as relevant for the therapeutic activity of another antibody-derived peptide. We evaluated the contribution of each residue to the peptide self-assembling capability by circular-dichroism spectroscopy. The interaction of the N10K peptide and its derivatives withCandida albicanscells was studied by confocal, transmission, and scanning electron microscopy. The apoptosis and autophagy induction profiles in yeast cells treated with the peptides were evaluated by flow cytometry, and the therapeutic efficacy against candidal infection was studied in aGalleria mellonellamodel. Overall, the results indicate a critical role for some residues in the self-assembly process and a correlation of that capability with the candidacidal activities of the peptidesin vitroand their therapeutic effectsin vivo.

Primary alveolar soft part sarcoma of uterine corpus: a case report with immunohistochemical, ultrastructural study and review of literature.

BACKGROUND: Alveolar soft part sarcoma (ASPS) is a rare mesenchymal malignancy. ASPS usually occurs most commonly in the deep soft tissues of the thigh and buttock or the head and neck regions. ASPS that originate from the uterine corpus are even more rare, with only 10 previous cases reported in the English literature. CASE PRESENTATION: In our case, the alveolar features were completely lost and the tumour shows a solid, non-alveolar pattern and the nuclei have marked variation in nuclear size, and multinucleation. The correct pathological diagnosis has been made by immuno- histochemical and ultrastructural features, which rvealed overexpression of TFE3 and peculiar cytoplasmic crystalline inclusions. In this paper, an additional case of primary ASPS of uterine corpus is reported with immunohistochemical, ultrastructural study and review of literature in the effort to delineate its clinical and pathological features. In this unusual site, the diagnosis can be problematic because ASPS can mimic other primary or metastatic uterine neoplasms. CONCLUSIONS: Thus, in this unusual presentation an essential diagnostic marker is the nuclear over-expression of TFE3 as well as ultrastructural study, which reveals the presence of peculiar cytoplasmic crystalline inclusions.

Adenomatous polyposis coli gene involvement in ileal enterochromaffin cell neuroendocrine neoplasms.

The adenomatous polyposis coli gene is a key tumor suppressor gene. Alterations in this gene have been found in most sporadic colon cancers; associated with familial adenomatous polyposis; and found in neoplasms of other organs, such as the liver, stomach, lung, breast, and cerebellar medulloblastoma. In the heterogeneous group of neuroendocrine neoplasms of the gastrointestinal tract, the involvement of adenomatous polyposis coli is debated, and only occasional reports found adenomatous polyposis coli alterations in foregut and midgut neuroendocrine neoplasms, with adenomatous polyposis coli mutations only in the latter. To elucidate the penetrance of adenomatous polyposis coli alterations in ileal neuroendocrine neoplasms, we performed DNA fragment analysis (loss of heterozygosity for 5q22-23 and 5q23) and sequencing on the mutation cluster region of the adenomatous polyposis coli gene on 30 ileal enterochromaffin cell neuroendocrine neoplasms. Adenomatous polyposis coli gene mutations were detected in 23% of cases (7/30); in particular, 57% were missense and 14%, nonsense/frameshift, all novel and different from those reported in colorectal or other cancers. Loss of heterozygosity analysis demonstrated a deletion frequency of 15% (4/27). No association was found with features of tumor progression. Our observations support the involvement of somatic adenomatous polyposis coli alterations in tumorigenesis of ileal enterochromaffin cell neuroendocrine neoplasms; the mechanisms of adenomatous polyposis coli gene inactivation appear to be different from those reported in other tumor types.

Primary squamous cell carcinoma of the endometrium unrelated to human papilloma virus: a molecular study.

In this paper we report a molecular study of a case of Primary Endometrial Squamous Carcinoma (PESC), in which a Human Papilloma Virus (HPV) infection had been previously excluded by Polymerase Chain Reaction (PCR). The studies performed in an effort to explain the carcinogenesis included immunohistochemical over-expression of p53 and p16 proteins as previously observed in our own papers, plus microsatellite analysis of D10S1765 at 10q23.3 (PTEN) and TP53 at 17p13.1 (P53) as well as the methylation status of the of BRCA1 and p16 promoters using specific PCRs. In this rare malignancy, we found allelic imbalance (AI) at 17p13.1 (P53). Instead, AI at D10S1765 (PTEN) gene was absent. The genetic alteration of p53, with hyper-expression of p53 protein and an absence of abnormalities in the PTEN gene are consistent with the similarities between Uterine Serous Carcinoma (USC) and our case of PESC. The aberrant methylation of both p16 and BCAR1 promoters was not detected in our case. This finding too could imply that ESC is more similar to Uterine Serous Carcinoma than Uterine Endometrioid Carcinoma (UEC). Moreover, the lack of aberrant methylation of p16, which is in accordance with over-expression of p16 immunoreactivity, in the absence of HPV infection may be related to other unknown genetic alterations. In our opinion, it is hard to reach any definite conclusion concerning the carcinogenesis of PESC, because of its rarity and the very few molecular studies reported in the literature. Further studies with more numerous cases and larger molecular analyses are mandatory for this malignancy, to confirm whether it is more closely related to papillary endometrial cancer than to endometrioid carcinoma.

Peptides of the constant region of antibodies display fungicidal activity.

Synthetic peptides with sequences identical to fragments of the constant region of different classes (IgG, IgM, IgA) of antibodies (Fc-peptides) exerted a fungicidal activity in vitro against pathogenic yeasts, such as Candida albicans, Candida glabrata, Cryptococcus neoformans, and Malassezia furfur, including caspofungin and triazole resistant strains. Alanine-substituted derivatives of fungicidal Fc-peptides, tested to evaluate the critical role of each residue, displayed unaltered, increased or decreased candidacidal activity in vitro. An Fc-peptide, included in all human IgGs, displayed a therapeutic effect against experimental mucosal and systemic candidiasis in mouse models. It is intriguing to hypothesize that some Fc-peptides may influence the antifungal immune response and constitute the basis for devising new antifungal agents.

A new case of primary signet-ring cell carcinoma of the cervix with prominent endometrial and myometrial involvement: Immunohistochemical and molecular studies and review of the literature.

BACKGROUND: As a rule, endocervical tumours with signet-ring cell are classed as metastatic extra-genital neoplasms. In a patient aged 45 years, we describe primary cervical signet-ring cell carcinoma (PCSRCC) characterized by prominent endometrial and myometrial involvement, simulating primary endometrial adenocarcinoma with cervical extension. In addition, a review was made of the literature to identify the clinical and pathological features of this rare malignancy. CASE PRESENTATION: A 45-year-old woman was referred to our Gynaecology Department due to persistent abnormal vaginal bleeding. Transvaginal ultrasonography showed slight endometrial irregularities in the whole uterine cavity suggestive of endometrial neoplasms. Pelvic magnetic resonance imaging revealed diffuse enlargement of the cervix, which had been replaced by a mass. Induration extended to the parametria and sigmoid colon fat.Histological examination of endometrial curettage and a cervical biopsy revealed a neoplasm characterized by neoplastic signet-ring cells and trabecular structures. Immunohistochemical analysis and molecular studies showed certain findings consistent with a cervical neoplasm, such as positivity to CEA, keratin 7, Ca-125 and p16 and the presence of HPV (Human Papilloma Virus) DNA 18.On examination of the hysterectomy with bilateral salpingo-oophorectomy and pelvic lymphadenectomy, the lesion replacing the cervix, endometrium and myometrium, revealed the same immunohistochemical findings observed on endometrial curettage and cervical biopsy specimens. Metastases were found in an ovarian cystic lesion and the lymph nodes. CONCLUSION: With this report the authors have demonstrated that the spread of cervical adenocarcinoma to the uterine corpus, although rare, may be observed, and that in this instance immunohistochemical and molecular studies can provide sufficient information for accurate diagnosis even on small biopsy specimens.

Two cases of low-grade endometriod carcinoma associated with undifferentiated carcinoma of the uterus (dedifferentiated carcinoma): a molecular study.

Dedifferentiated carcinoma (DC) is an uterine neoplasm containing both low-grade endometrioid carcinoma (LGEC) and undifferentiated carcinoma (UC). DC is an aggressive tumour even when the UC component represents only 20% of the entire neoplasm. In this paper, two cases DCs at different stages of development, in 61- and 83-year-old women respectively were reported. In addition, in these uterine malignancies microsatellite instability (MSI) and loss of heterozygosity (LOH) were investigated in order to explain its aggressive behavior, in both components. Case #1 presented metastases at diagnosis, while case #2 was at a lower stage. LGEC component was invasive in case #1 and intramucous in case #2. In both cases, UC components were characterized by a high degree of instability, in accordance of its aggressive behaviour and its architectural heterogeneity. Further studies with more numerous cases are mandatory to confirm these data.

Metaplastic papillary tumor of the salpinx: report of a case using microsatellite analysis.

Metaplastic papillary tumor (MPT) of the salpinx is a rare lesion found in the lumen of fallopian tubes during the postpartum period. This lesion is very small and is composed microscopically of papillae lined by stratified epithelium. Similar to serous borderline ovarian tumors (BOTs), epithelial elements of MPT show a budding, abundant, dense, and eosinophilic cytoplasm, bland nuclei or with mild atypia. It is not clear whether this lesion is a papillary metaplastic proliferation or a small atypical proliferative (borderline) serous tumor associated with pregnancy. Owing to its rarity, MPT has never been investigated in molecular studies and compared with ovarian serous neoplasms. In this study, a case of tubal MPT was molecularly examined and compared with 4 BOTs and with 2 low-grade ovarian carcinomas, using microsatellite analysis with 13 markers at 8 chromosomal regions involved in ovarian carcinogenesis. The tubal MPT and one of the BOTs showed no alterations in the investigated chromosomal regions. The remaining 3 BOTs showed only single allelic imbalances. Instead, low-grade serous carcinomas showed a higher frequency of alterations, including allelic imbalance at chr10q23, 1p36, 9p22, and 17. In conclusion, this study provides, for the first time, molecular data on an MPT of the fallopian tube, indicating that this entity might share both morphologic and molecular similarities with a subset of minimally altered BOTs, termed atypical proliferative serous tumors, which behave in a benign manner. However, in our opinion, further molecular studies should be conducted on other cases of MPTs to confirm this hypothesis.

Involvement of HER-2/neu and metastasis-related proteins in the development of ileal neuroendocrine tumors.

HER-2/neu overexpression and/or gene amplification occurs in several human malignancies, frequently correlates with tumor aggressiveness, and provides the basis for treatment with trastuzumab. Among neuroendocrine neoplasms (NEN) of the gastroenteropancreatic (GEP) tract, ileal neuroendocrine tumors show peculiar features of malignancy with frequent metastases at the diagnosis. We investigated the overexpression and/or amplification of HER-2/neu and the involvement of the metastasis-related proteins c-Met, MTA-1, and VEGF in 24 primary ileal NEN by immunohistochemistry and fluorescence in situ hybridization (FISH). Data were compared with those of 43 GEP endocrine tumors of other sites. All primary ileal NEN showed an intense membranous and cytoplasmic immunostaining for HER-2/neu. According to the breast cancer scoring system, 17% of ileal carcinoids showed a score of 3+ and 71% with a score of 2+ with a significant difference respect the non-ileal GEP endocrine tumors (p < 0.0000). FISH analysis revealed chromosome 17 polysomy in 33% of 2+/3+ ileal tumors but not HER-2/neu gene amplification. The c-Met and MTA-1 but not VEGF were overexpressed in almost all ileal NEN, whereas VEGF presented more frequently a normal staining. The comparisons with the other GEP NEN demonstrated significant differences for all the three proteins (p < 0.0000, p < 0.0002, and p < 0.001, respectively). These findings suggest that in ileal NEN, HER-2/neu overexpression plays a role in the carcinogenetic process and by triggering the altered expression of c-Met and MTA-1, may activate the molecular pathway(s) promoting tumor progression and metastasis development. Ileal HER-2/neu overexpressing neuroendrocrine tumors may constitute potential candidates for target therapy with specific humanized monoclonal antibodies.

Clinicopathologic implications of the epidermal growth factor receptor, cyclooxygenase 2 expression, and human papillomavirus status in squamous cell carcinoma of the uterine cervix in the elderly.

OBJECTIVES: To find information on invasive squamous cervical carcinoma in the elderly, 110 invasive squamous cervical carcinomas obtained from 2 groups of patients (aged <60 and >60 years) were analyzed for human papillomavirus (HPV) status by polymerase chain reaction study, for immunohistochemical epidermal growth factor receptor (EGFR), cyclooxygenase 2 (Cox-2) expression, and clinicopathologic features. METHODS: The HPV status and the expression of Cox-2 and EGFR in the younger and older women were compared and correlated with the grading, staging neoplasm, and lymph nodal status, using Fisher test and Spearman nonparametric correlation test. Overall survival curves were drawn using Kaplan-Meier estimates and were compared using log-rank tests in the whole series of 110 patients. Multinomial logistic regression was also used. RESULTS AND CONCLUSIONS: The number of neoplasms with higher staging was significantly greater than those in the younger women (P = 0.04). The mortality was higher in the older group than in the younger patients (P = 0.006).In the elderly, the presence of HPV DNA in 65% of cases, and in the absence of sexual activity, could be due to reactivation of latent HPV infection, which might be due to an impairment of host immunologic response.The overexpression of Cox-2 in a number of cases was significantly higher in the older group than in the younger group (P = 0.032, Fisher exact test), but this immunoreactivity is not related to the staging, grading, EGFR expression, or to the presence of HPV.The simultaneous expression of Cox-2 and EGFR had a poor prognostic significance, showing lower survival rates than cases without this immunoreactivity (P = 0.002), on univariate analysis.On multivariate analysis, Cox-2 and EGFR immunopositivity did not reveal any correlation between these markers and prognosis probably because the number of cases considered was not particularly high.

A Unique case of primary squamous carcinoma of the salpinx associated with serous carcinoma of the omentum: a pathological and molecular study.

In this article, we report a case of primary squamous cell carcinoma of the salpinx (PSCCS) with immunohistochemical and molecular studies to evaluate the phenotype and define the etiopathogenesis of this neoplasm. A 77-year-old woman, 38 years postmenopausal, was admitted to the Department of Obstetrics and Gynecology for ascites. Her clinical history showed breast carcinoma and left salpingooophorectomy as a result of extrauterine pregnancy. Cytological examination of the free peritoneal fluid showed clusters of malignant cells consistent with ovarian carcinoma. Transvaginal ultrasonography and a pelvic computed tomography scan disclosed a right pelvic mass with solid and cystic areas, measuring 3.222.3 cm. The patient underwent exploratory laparotomy. Intraoperative findings showed a mass that had replaced the salpinx and enveloped the ovary and ureter. The surface of the omentum was covered in small white nodules. Pathological examination showed that the right pelvic mass corresponded to PSCCS, whereas the omental white nodules were primary serous carcinoma. On immunohistochemical analysis, the tubal neoplasm showed positivity to Ca-125, keratin 14, and p63 and negativity to WT1 and p16. The hyper-expression of the p53 protein was evident as nuclear positivity. Molecular study by polymerase chain reaction amplification of the tumor DNA did not show any signal for human papilloma virus DNA. In summary, in this case we showed that the PSCCS was not due to human papilloma virus infection, but in all probability due to other pathogenetic mechanisms that cause a mutation of the p53 tumor-suppressor gene.

Uterine carcinosarcoma metastatic to the lung as large-cell neuroendocrine carcinoma with synchronous sarcoid granulomatosis.

A 58-year-old woman underwent a curative total abdominal hysterectomy with bilateral salpingo-oophorectomy for a uterine carcinosarcoma. Fifteen months later, PET and CT scan revealed three pulmonary nodules and multiple lymphadenopathy. An atypical lung segmentectomy with dissection of the regional lymph nodes was performed. Two of the three nodules showed morphological and immunohistochemical profiles consistent with the diagnosis of large-cell neuroendocrine carcinoma (LCNEC). The third nodule, the surrounding pulmonary parenchyma and lymph nodes showed diffuse sarcoid granulomatosis. Re-review of the histology of the uterine carcinosarcoma revealed LCNEC morphology with immunohistochemical and genetic profiles identical to the lung cancers, finally deemed as metastatic deposits. Systemic sarcoidosis was ruled out. To our knowledge this is the first case of uterine carcinosarcoma with LCNEC features metastatic to the lung and occurring in association with sarcoid reaction.

Primary moderately differentiated neuroendocrine carcinoma (atypical carcinoid) of the larynx: A case report with immunohistochemical and molecular study.

Neuroendocrine tumours are the second most common laryngeal neoplasms, following squamous carcinoma. In this paper, we report the case of a moderately differentiated neuroendocrine carcinoma NEC (atypical carcinoid) of the larynx in a heavy smoker 67-year-old woman, with a history of hoarseness, dysphagia and dyspnea. The lesion was biopsied and microscopic examination revealed moderately differentiated NEC; thus the patient underwent supraglottic laryngectomy with lymphadenectomy. Here, we emphasized the morphological criteria for a correct pathological diagnosis. Moreover, because it has been demonstrated that many neuroendocrine neoplasms and malignant lesions of the larynx can be related to human papilloma virus (HPV), for the first time, we probed to verify if laryngeal neuroendocrine carcinoma could be due to an HPV infection by using polymerase chain reaction amplification (PCR) of tumoural DNA. On immunohistochemical analysis, the lesion characteristically revealed both neuroendocrine and epithelial differentiation with diffuse staining for chromogranin A, synaptophysin and neuron-specific enolase (NSE) and epithelial membrane antigen (EMA) and overexpression of p53 protein. PCR of NEC DNA did not show any signal for HPV DNA. Thus, this neoplasm is not due to an HPV infection, but a mutation of p53 gene which could cause immunohistochemical overexpression of p53 protein.

Adenomatous polyposis coli alteration in digestive endocrine tumours: correlation with nuclear translocation of beta-catenin and chromosomal instability.

The role of Wnt pathway in digestive endocrine tumours is debated. The aim of this work is to investigate key players in Wnt pathway by a multimodal approach. Sixty cases (49 well-differentiated and 11 poorly differentiated) were investigated for methylation of adenomatous polyposis coli (APC) and E-cadherin promoters, the loss of heterozygosity (LOH) at APC locus and beta-catenin and E-cadherin expression by immunohistochemistry. Tumours showing altered beta-catenin localization were tested for beta-catenin and APC mutations. APC promoter methylation was restricted to gastroduodenal tumours (21 out of 59, 36%), prevalent in poorly differentiated carcinomas (P=0.042) and correlating with aggressive features (high histology grade, P<0.02; tumour death, P=0.026; high fractional allelic loss, P=0.002, in turn correlating with short survival, P=0.017). LOH at APC locus was found in 14 out of 53 cases (26%, 10 gastroduodenal and 4 colorectal), prevalent in poorly differentiated carcinomas (P=0.002) and correlating with histology grade (P=0.012). beta-catenin abnormal expression was found in 41 out of 54 cases (76%), with nuclear staining correlating with APC alteration (P=0.047) and short survival (P=0.006). APC, but not beta-catenin, gene mutations were found (7 out of 35 tumours), 4 of which in the midgut. E-cadherin promoter methylation was rarely detected (2 out of 52 cases), with cytoplasmic expression in 18 out of 43 cases (42%), not correlating with any clinico-pathological feature. In conclusion, Wnt pathway alterations, as represented by abnormal beta-catenin localization, are common events in digestive endocrine tumours, but only nuclear expression correlates with tumour aggressiveness. Though with different alteration mechanisms according to anatomical site, APC plays a major role in Wnt pathway activation and in determining the high chromosomal instability observed in aggressive endocrine carcinomas.

Genetics of a combined lung small cell carcinoma and large cell neuroendocrine carcinoma with adenocarcinoma.

Combined nonneuroendocrine-neuroendocrine lung tumors are relatively infrequent and little is known as for their genetic basis. Here, we report the case of a 69-year-old male with a solitary neoplasm in the upper lobe of the right lung. At histological examination, the tumor showed two components. The main part was an adenocarcinoma of the acinar type. The second part showed morphological and immunohistochemical phenotype of a neuroendocrine carcinoma composed of a small cell lung carcinoma and a large cell neuroendocrine carcinoma. The aim of our study was to investigate the genetic relationship between neuroendocrine and nonneuroendocrine tumor components. To this purpose, we performed a loss of heterozygosity (LOH) analysis with 40 chromosomal microsatellite markers. Microallelotyping revealed a common genetic profile in the different tumor areas. In 9 of 30 informative regions analyzed, LOH involved the same allele in all components, regardless of their histological type and grade. These findings support the true combined nature of this exocrine-neuroendocrine carcinoma of the lung and suggest a common monoclonal origin from a pluripotent epithelial (alveolar or bronchial) precursor cell for the two different tumor components.