Frozen section assessment in testicular and paratesticular lesions suspicious for malignancy: its role in preventing unnecessary orchiectomy.

To investigate the role of frozen section assessment in sparing unnecessary orchiectomy for suspected lesions, we retrospectively reviewed intraoperative testicular and paratesticular frozen section assessments performed at our institution between the years 1993 and 2010. Frozen section assessments were performed on 45 testicular lesions (age, 5-60 [mean, 32.2] years; lesion size, 0.5-9.7 [mean, 2.1] cm) and 20 paratesticular lesions (age, 26-76 [mean, 43.5] years; lesion size, 0.4-11.0 [mean, 2.8] cm) before the decision to complete radical orchiectomy. Benign/malignant frozen section assessment diagnoses were reported in 26/19 testicular cases and 17/3 paratesticular cases, respectively. Of the 26 benign testicular frozen section assessments, 5 cases resulted in orchiectomy, where permanent diagnoses included epidermoid cyst, large cell calcifying Sertoli cell tumor, fibrous pseudotumor, abscesses, and sarcoidosis, caused by a concern for potential malignancy or questionable viability of the testicles. Of the 19 malignant testicular frozen section assessments, orchiectomy was performed in 16 cases with germ cell tumor, but not in the remaining 3 cases with lymphoma. Of the 17 benign paratesticular frozen section assessments, 2 cases, both fibrous pseudotumors, resulted in orchiectomy. There were statistically significant differences in the size of the testicular (P < .001) or paratesticular (P < .001) lesions between benign and malignant frozen section assessments. Thus, in 36 (83.7%) of 43 cases with benign frozen section assessments, in addition to all 3 cases of lymphoma, orchiectomy was successfully avoided. These results suggest that frozen section assessment is useful for permitting testicular preservation, especially in men with small, nonpalpable, incidentally found masses as well as other benign lesions where a clinical diagnosis of malignancy is in doubt.

CD44 expression is a feature of prostatic small cell carcinoma and distinguishes it from its mimickers.

Small cell neuroendocrine carcinoma of the prostate is a rare variant of prostatic cancer that shares morphologic similarity with prostatic adenocarcinoma of Gleason 5 pattern. It has also been considered morphologically and immunohistochemically indistinguishable from small cell neuroendocrine carcinomas of other origins. CD44 is a cell-surface molecule proposed to identify cancer stem/progenitor cells in prostate cancer. We performed immunohistochemical study for CD44 expression in 11 cases of prostatic small cell neuroendocrine carcinoma and compared its patterns of expression with 73 cases of prostatic adenocarcinoma and 47 cases of small cell neuroendocrine carcinomas of other organs. Strong and diffuse membrane staining for CD44 was observed in 100% of the prostatic small cell neuroendocrine carcinomas. In conventional adenocarcinomas of the prostate, positive staining was only seen in rare, scattered tumor cells; and CD44 staining was negative in most of the small cell neuroendocrine carcinomas of nonprostate origin. The difference in CD44 expression between small cell neuroendocrine carcinomas of the prostate and those of other organs are statistically significant (P < .001). Our study demonstrates the utility of immunohistochemical staining for CD44 in distinguishing prostatic small cell neuroendocrine carcinoma from its mimickers including prostatic adenocarcinoma of Gleason 5 pattern and small cell neuroendocrine carcinomas of other organs. CD44 is the first marker that shows a high degree of tissue/organ specificity for small cell neuroendocrine carcinomas. Because CD44 is a putative marker of prostate cancer stem cells, the strong and diffuse expression of CD44 and the lack of expression of prostate luminal differentiation markers androgen receptor and prostatic specific antigen in prostatic small cell neuroendocrine carcinomas suggest that the tumor cells may retain cancer stem cell features.

Tissue elasticity properties as biomarkers for prostate cancer.

In this paper we evaluate tissue elasticity as a longstanding but qualitative biomarker for prostate cancer and sonoelastography as an emerging imaging tool for providing qualitative and quantitative measurements of prostate tissue stiffness. A Kelvin-Voigt Fractional Derivative (KVFD) viscoelastic model was used to characterize mechanical stress relaxation data measured from human prostate tissue samples. Mechanical testing results revealed that the viscosity parameter for cancerous prostate tissue is greater than that derived from normal tissue by a factor of approximately 2.4. It was also determined that a significant difference exists between normal and cancerous prostate tissue stiffness (p < 0.01) yielding an average elastic contrast that increases from 2.1 at 0.1 Hz to 2.5 at 150 Hz. Qualitative sonoelastographic results show promise for cancer detection in prostate and may prove to be an effective adjunct imaging technique for biopsy guidance. Elasticity images obtained with quantitative sonoelastography agree with mechanical testing and histological results. Overall, results indicate tissue elasticity is a promising biomarker for prostate cancer.

Mucinous tubular and spindle cell carcinoma of the kidney with sarcomatoid differentiation.

We report a unique case of mucinous tubular and spindle cell carcinoma (MTSC) of the kidney with extensive sarcomatoid differentiation, multiple metastases, and a rapidly fatal clinical course. The patient presented with back pain and a pathologic L1 fracture. Diagnostic imaging revealed a large retroperitoneal mass arising from the left kidney and compressing the spinal cord. Radiotherapy and surgery were performed, but the patient died from disease progression three weeks postoperatively. MTSC is a recently recognized entity that is considered to be a low-grade carcinoma with a favorable prognosis. Our case demonstrates that although MTSC is usually a low-grade carcinoma, sarcomatoid differentiation may occur and lead to a fatal course, as in all other types of renal cell carcinomas. Adequate sampling and the exclusion of sarcomatoid differentiation in the spindle cell component are necessary for proper management and prognostication. To our knowledge, this is the first reported case of MTSC with sarcomatoid differentiation and a fatal outcome.

Expression of claudin-7 in benign kidney and kidney tumors.

Claudins, a family of tight junction-related transmembrane proteins, have been implicated in the pathogenesis of various human neoplasms. Expression of claudin-7 was increased in chromophobe renal cell carcinoma in a recent oligonucleotide microarray study. We studied the expression of claudin-7 in benign and neoplastic kidneys by immunohistochemical staining. Distal nephron (distal convoluted tubule and thick ascending limb of Henle's loop) epithelium showed strong membranous staining in 100% (174/174) of the cases. Chromophobe renal cell carcinoma was positive for claudin-7 expression in 100% (36/36) of cases, while papillary renal cell carcinoma, oncocytoma and clear cell renal cell carcinoma were positive in 90% (71/80), 45% (21/47) and 7% (7/98) of the cases, respectively. Differential expression of Claudin-7 in different types of renal cell neoplasms can be useful in their differential diagnosis, particularly when used in a panel of markers. In addition, results from this study support previous reports of distal nephron origin for chromophobe renal cell carcinoma and oncocytoma. The data also suggest that, as far as claudin-7 expression is concerned, papillary renal cell carcinoma may be more closely related to the distal nephron, rather than the proximal nephron.

Expression of RNA-binding protein IMP3 (KOC) in benign urothelium and urothelial tumors.

RNA-binding protein IMP3 is a KH-domain-containing protein and a member of the insulin-like growth factor messenger RNA-binding protein family. It is identical to K-homology protein overexpressed in cancer that was identified through screening for genes differentially expressed between benign pancreatic tissue and pancreatic cancer. Several studies have shown that IMP3 is associated with aggressive and advanced tumors in various organs. We studied the expression of IMP3 in benign urothelium and urothelial tumors by immunohistochemistry. The expression pattern of IMP3 was further compared with that of p53 and p16. Our study shows that IMP3 is generally not expressed in benign urothelium or low-grade urothelial tumors including urothelial dysplasia, papillary urothelial neoplasm of low malignant potential, and low-grade papillary urothelial carcinoma. The expression of IMP3 is significantly increased in high-grade urothelial tumors including high-grade papillary urothelial carcinoma, urothelial carcinoma in situ, and invasive urothelial carcinoma. Expression of IMP3 in urothelial tumors parallels the accumulation of nuclear p53, although there is not always a one to one correlation. In contrast, expression of p16 in the different groups of urothelial tumors is more variable. Urothelial carcinomas with invasion of muscularis propria appear to express IMP3 more frequently than lower-stage tumors. These findings suggest that IMP3 may be involved in the progression of urothelial tumors from low grade to high grade in both papillary and flat lesions. Immunohistochemical detection of the combined expression of IMP3 and p53 is useful in the diagnosis of high-grade urothelial tumors, particularly in small, superficial materials.

Function and molecular mechanisms of neuroendocrine cells in prostate cancer.

Benign prostate contains luminal epithelial cells, basal cells and a minor component of neuroendocrine cells whose function may be to regulate the growth, differentiation and secretory function of the prostate gland. Neuroendocrine (NE) cells are also present in prostate cancer (PC), and many studies have shown that their number increases in high-grade and high-stage tumors, particularly in hormonally treated and hormone-refractory (androgen independent) PC. Unlike the non-neuroendocrine secretory-type PC cells, NE cells lack androgen receptor and are likely androgen independent. Therefore it is conceivable that hormonal therapy for advanced or metastatic prostate cancer, which consists of inhibiting androgen production or blocking androgen function, will not eliminate NE cancer cells. Instead, these cells may be enriched after the therapy and they may establish paracrine networks to stimulate androgen-independent proliferation of PC, leading to tumor recurrence. This article reviews the major functions of NE cells in PC, including stimulation of cancer proliferation and invasion, apoptosis resistance and angiogenesis. It also discusses molecular pathways involved in NE differentiation and the effectors of the NE cells.

Transgelin functions as a suppressor via inhibition of ARA54-enhanced androgen receptor transactivation and prostate cancer cell growth.

The androgen receptor (AR) requires coregulators for its optimal function. However, whether AR coregulators further need interacting protein(s) for their proper function remains unclear. Here we describe transgelin as the first ARA54-associated negative modulator for AR. Transgelin suppressed ARA54-enhanced AR function in ARA54-positive, but not in ARA54-negative, cells. Transgelin suppressed AR transactivation via interruption of ARA54 homodimerization and AR-ARA54 heterodimerization, resulting in the cytoplasmic retention of AR and ARA54. Stable transfection of transgelin in LNCaP cells suppressed AR-mediated cell growth and prostate-specific antigen expression, whereas this suppressive effect was abolished by the addition of ARA54-small interfering RNA. Results from tissue surveys showing decreased expression of transgelin in prostate cancer specimens further strengthened the suppressor role of transgelin. Our findings reveal the novel mechanisms of how transgelin functions as a suppressor to inhibit prostate cancer cell growth. They also demonstrate that AR coregulators, like ARA54, might have dual in vivo roles functioning as both a direct coactivator and as an indirect mediator in AR function. The finding that a protein can modulate AR function without direct interaction with AR might provide a new therapeutic approach, with fewer side effects, to battle prostate cancer by targeting AR indirectly.

Suppression of androgen receptor transactivation and prostate cancer cell growth by heterogeneous nuclear ribonucleoprotein A1 via interaction with androgen receptor coregulator ARA54.

The androgen receptor (AR) requires coregulators for its optimal transactivation. Whether AR coregulators also need interacting proteins to modulate their function remains unclear. Here we describe heterogeneous nuclear ribonucleoprotein (hnRNP) A1 as an associated negative modulator for the AR coregulator ARA54. hnRNP A1 selectively suppressed ARA54-enhanced wild-type and mutant AR transactivation via interruption of AR-ARA54 interaction and ARA54 homodimerization. Stable transfection of hnRNP A1 in the LNCaP cells suppressed AR-mediated cell growth and the expression of prostate-specific antigen, and this suppressive effect was abolished by the addition of ARA54-small interfering RNA. Small interfering RNA knockdown of endogenous hnRNP A1 enhanced cell growth and prostate-specific antigen expression in LNCaP cells. These results not only suggest that the loss of hnRNP A1 expression might activate the ARA54-enhanced cell growth and contribute to the prostate cancer progression, but also demonstrate the dual functional roles for ARA54 as an AR coregulator directly and as a mediator for the suppressive effect of hnRNP A1 indirectly. The novel finding that a protein can modulate AR function without direct interaction with AR might provide a new therapeutic approach to battle prostate cancer by targeting AR indirectly with fewer side effects.

Soft tissue tumors of the prostate: a review.

Prostate cancer is a leading cause of cancer-related death in adult men. Some prostates that are suspected to be involved by prostatic adenocarcinoma or nodular prostatic hyperplasia through clinical examination and imaging studies proves on histologic examination to be a soft tissue tumor. This paper outlines the most common soft tissue tumors of the prostate and categorizes them into benign, malignant or miscellaneous. Pathologists must be aware that most, if not all, soft tissue tumors of the body may also be found in the prostate. Diagnostic immunohistochemistry is an important adjunct to histopathology for proper diagnosis and tumor subclassification.

Androgen receptor in sertoli cell is essential for germ cell nursery and junctional complex formation in mouse testes.

To examine the role of androgen receptor (AR) in Sertoli cells (SC), we used a SC-specific AR knockout (S-AR-/y) mouse to further evaluate the chronological changes of seminiferous tubules and the molecular mechanisms of SC androgen/AR signals on spermatogenesis. Testes morphology began changing as early as postnatal day (PD) 10.5 in wild-type (WT), but not in S-AR-/y mice. After puberty (PD 50), the SC nuclei of WT testes migrated to the basal area of the seminiferous epithelium; however, in S-AR-/y testes, SC nuclei were disarranged and dislocated. Results from electron microscopy further showed an obvious duplication of basal lamina of the seminiferous epithelium in S-AR-/y testes at PD 50 compared with WT testes. Using quantitative RT-PCR analyses, the expression of SC gene profiles were compared in PD 10.5 testes. In S-AR-/y testes, the expression levels of 1) vimentin were significantly increased and laminin alpha5 was significantly decreased in PD 10.5, which contributed to functional defects in cytoskeletons and production of the basement membrane component of SC leading to cell morphology deterioration and thus affecting the integrity of seminiferous epithelium; 2) claudin-11, occludin, and gelsolin were significantly decreased in PD 10.5, which contributed to defects in intact junctional complex formation of SC leading to impairment of the integrity of the blood-testis barrier; 3) calcium channel, voltage-dependent, P/Q-type, alpha1A subunit; tissue-type plasminogen activator; transferrin; and epidermal fatty-acid-binding protein were significantly decreased in PD 10.5, which contributed to functional defects in production and/or secretion of specific proteases, transport proteins, and paracrine factors of SC, leading to impairment of its germ cells' nursery functions.

Immunohistochemical characterization of neuroendocrine cells in prostate cancer.

BACKGROUND: Neuroendocrine (NE) cells increase in high grade/stage prostate cancer (PC) and may contribute to androgen-independent cancer. Their immunohistochemical phenotype has not been studied in detail and conflicting results have been reported. METHODS: PC tissue was stained immunohistochemically for luminal secretory cell-associated cytokeratin, basal cell markers, ki-67, androgen receptor (AR), PSA, prostate acid phosphatase (PAP), and alpha-methylacyl coenzyme A racemase (AMACR). RESULTS: The NE cells are positive for AE1/AE3, Cam 5.2, and negative for basal cell markers. They are negative for AR, PSA, and Ki-67 but positive for PAP. The benign NE cells are negative for AMACR while the malignant NE cells are positive for AMACR. CONCLUSIONS: NE cells of PC constitute a unique subset of cancer cells, which have a unique immunohistochemical profile. They do not express AR, consistent with their resistance to hormonal therapy. They are post-mitotic cells but are malignant and part of the tumor.

Protein tyrosine phosphatase PTP1B is involved in neuroendocrine differentiation of prostate cancer.

BACKGROUND: Prostate cancer (PC) contains a minor component of neuroendocrine (NE) cells that may stimulate androgen-independent growth of the tumor. The mechanism of neuroendocrine differentiation remains unknown. METHODS: The expression of PTP1B, a protein tyrosine phosphatase, was studied in LNCaP cells induced to show neuroendocrine phenotype by androgen withdrawal. Wild-type PTP1B and its dominant-negative mutant were transfected into LNCaP cells to study their effects on neuroendocrine differentiation. In vivo expression of PTP1B in human prostate cancer was studied by immunohistochemistry. RESULTS: Androgen withdrawal of LNCaP cells led to increased expression of PTP1B with a corresponding increase in its tyrosine phosphatase activity. Overexpression of PTP1B in LNCaP cells led to neuroendocrine differentiation while expression of its dominant-negative mutant inhibited neuroendocrine differentiation. Immunohistochemical study showed that PTP1B was exclusively expressed in neuroendocrine cells of human prostate cancer tissue. CONCLUSION: Our findings suggest that PTP1B plays an important role in neuroendocrine differentiation, and therefore, may possibly be involved in the progression of prostate cancer.

Prostate cancer: three-dimensional sonoelastography for in vitro detection.

PURPOSE: To prospectively evaluate the accuracy of three-dimensional (3D) sonoelastographic imaging, relative to that of gray-scale ultrasonography (US), in the in vitro detection of prostate cancer. MATERIALS AND METHODS: The study was approved by the institutional review board and was HIPAA compliant. Informed consent was obtained from all patients. Nineteen prostatectomy specimens from patients aged 46-70 years with biopsy-proved prostate cancer were scanned in three dimensions by using conventional B-mode US and sonoelastography with vibrations of more than 100 Hz. Step-sectioned whole-mount histologic specimens were used to create a 3D volume of the prostate and the tumors within it. B-mode US scans and regions of low vibration on the sonoelastographic images (hard regions) were formatted in three dimensions. The lesions in the 19 cases were classified into two groups, as follows: G1 lesions were pathologically confirmed tumors with a volume of at least 1.0 cm3, and G2 lesions were pathologically confirmed tumors smaller than 1.0 cm3. G1 lesions were evaluated with B-mode US and sonoelastography and classified as true-positive, false-positive, true-negative, or false-negative; G2 lesions were evaluated only with sonoelastography. Findings at histologic examination were used as the reference standard. True-positive findings necessitated 3D lesion correlation between pathologic and imaging data. Conventional definitions of accuracy and sensitivity were used for statistical analysis. RESULTS: For G1 lesions (seven lesions with a volume of at least 1.0 cm3), sonoelastography had an accuracy of 55% and a sensitivity of 71% and B-mode US had an accuracy of 17% and a sensitivity of 29%. The mean tumor volume was 3.1 cm3 +/- 2.1 (standard deviation). For G2 lesions (22 lesions with a volume of less than 1.0 cm3), the mean tumor volume was 0.32 cm3 +/- 0.21. Sonoelastography had an accuracy of 34% and a sensitivity of 41%; there were six false-positive findings. CONCLUSION: Sonoelastography performed considerably better than did gray-scale US in the depiction of prostate cancer for tumors with volumes of more than 1 cm3.

Overexpression of decoy receptor 3 in precancerous lesions and adenocarcinoma of the esophagus.

Overexpression of decoy receptor (DcR) 3 protein, a recently discovered member of the tumor necrosis factor receptor superfamily, was examined in 40 esophagogastrectomy specimens containing areas of Barrett esophagus (n = 27), low-grade dysplasia (n = 27), high-grade dysplasia or carcinoma in situ (n = 22), and esophageal adenocarcinoma (EAC; n = 28) with immunohistochemical analysis. The results revealed significantly more overexpression of DcR3 in high-grade dysplasia or carcinoma in situ and EAC than in benign esophageal mucosa (both P < .0001), Barrett esophagus (both P < .001), and low-grade dysplasia (P < .01 and P = .033, respectively). Low-grade dysplasia also showed significant overexpression of DcR3 compared with benign esophagus (P < .05) but not with Barrett esophagus (P > .05). DcR3 overexpression seems to negatively correlate with the grade of EAC. Our results suggest that overexpression of DcR3 protein might aid in the diagnosis of high-grade dysplasia or carcinoma in situ and EAC and also might serve as a potential therapeutic target.

Differential expression of interleukin-8 and its receptors in the neuroendocrine and non-neuroendocrine compartments of prostate cancer.

Hormonal therapy (androgen ablation and/or inhibition of androgen action) is the treatment of choice for advanced prostate cancer. After an initial response in most patients, tumors invariably progress to an androgen-independent state. It is unclear how prostate cancer cells proliferate without androgen. Recent studies suggest that interleukin-8 may promote androgen-independent proliferation, but the source of interleukin-8 in the prostate is unknown. Using immunohistochemistry, we show that interleukin-8 was expressed by the neuroendocrine tumor cells in human prostate cancer tissue. Expression of the interleukin-8 receptor CXCR1 was negative or low in benign prostatic tissue and was frequently increased in malignant cells of high-grade prostatic intraepithelial neoplasia and prostate cancer; however, CXCR1 was not detected in the neuroendocrine tumor cells, suggesting a paracrine mechanism by which interleukin-8 produced by neuroendocrine tumor cells stimulates androgen-independent proliferation of prostate cancer. Neuroendocrine tumor cells expressed another type of interleukin-8 receptor, CXCR2, suggesting an autocrine mechanism by which interleukin-8 regulates the differentiation or function of the neuroendocrine cells. These results, combined with previous reports that neuroendocrine differentiation is induced by hormonal therapy, suggest that neuroendocrine cells play an important role in promoting androgen-independent growth of prostate cancer through interleukin-8 signaling.

Cell culture block array for immunocytochemical study of protein expression in cultured cells.

Immunocytochemical staining of cultured cells using specific antibodies is a powerful technique to study the expression and subcellular localization of proteins. However, this technique is associated with sample-to-sample variations because samples are handled individually and manually. Cell permeation is needed when intracytoplasmic or nuclear proteins are studied. Storage of cultured cells is difficult, and experiments must be repeated if additional studies are desired later, which introduces more variations. We developed a cell culture block array technique that converts cultured cells into a permanently fixed form identical to tissue sections prepared for pathologic examination. Cells from different cultures can be embedded in a single block. Many identical sections, each containing cells from multiple cultures, may be stained with different antibodies using an automated stainer. As a result, sample-to-sample variation is eliminated. Because cells in these blocks are sectioned by knives, all cellular proteins come into direct contact with antibodies, and cell permeation is not needed. Such blocks can be conveniently stored for years without loss of antigens, providing a constant source for future studies. We demonstrated the utility of this technique by studying the proliferation and neuroendocrine differentiation of prostate cancer-derived LNCaP cells cultured in vitro.

Frequent expression of human carcinoma-associated antigen, a mucin-type glycoprotein, in cells of prostatic carcinoma.

CONTEXT: Human carcinoma-associated antigen (HCA) is a mucin glycoprotein recognized by antibodies raised against epiglycanin, the latter having been originally purified from mouse mammary carcinoma cells. Human carcinoma-associated antigen expression is increased in sera of patients with various carcinomas, including prostatic carcinoma. However, to our knowledge, expression of HCA in benign and neoplastic prostatic tissue has not been studied. OBJECTIVE: To compare the expression of HCA in cells of primary and metastatic prostatic carcinomas with its expression in non-carcinoma-associated cells. DESIGN: We studied 40 cases of primary and 36 cases of metastatic prostatic carcinomas by immunohistochemical staining with anti-HCA monoclonal antibodies G1 and HAE3. The blocks from primary carcinomas also contained normal prostatic tissue (40 cases), benign prostatic hyperplasia (16 cases), and high-grade prostatic intraepithelial neoplasia (32 cases). RESULTS: The 2 antibodies stained carcinomas more frequently than normal prostatic tissue, hyperplasia, and prostatic intraepithelial neoplasia (P < .001). The differences in the staining of low-grade versus high-grade tumors was not statistically significant with either antibody. The staining was present in the cytoplasm and on the luminal membrane surface of the tumor cells and in the luminal secretions. In metastatic prostatic carcinomas, G1 and HAE3 staining was positive in 44% and 67% of the cases, respectively. CONCLUSIONS: Our results showed that mucin protein HCA is overexpressed in cells of prostatic carcinoma, which may have value in diagnosis and therapy. Its role in carcinogenesis also merits further study.