Immunohistochemical differentiation of high-grade prostate carcinoma from urothelial carcinoma

First-in-man evaluation of 2 high-affinity PSMA-avid small molecules for imaging prostate cancer

This phase 1 study was performed to determine the pharmacokinetics and ability to visualize prostate cancer in bone, soft-tissue, and the prostate gland using (123)I-MIP-1072 and (123)I-MIP-1095, novel radiolabeled small molecules targeting prostate-specific membrane antigen.

METHODS

Seven patients with a documented history of prostate cancer by histopathology or radiologic evidence of metastatic disease were intravenously administered 370 MBq (10 mCi) of (123)I-MIP-1072 and (123)I-MIP-1095 2 wk apart in a crossover trial design. (123)I-MIP-1072 was also studied in 6 healthy volunteers. Whole-body planar and SPECT/CT imaging was performed and pharmacokinetics studied over 2-3 d. Target-to-background ratios were calculated. Absorbed radiation doses were estimated using OLINDA/EXM.

RESULTS

(123)I-MIP-1072 and (123)I-MIP-1095 visualized lesions in soft tissue, bone, and the prostate gland within 0.5-1 h after injection, with retention beyond 48 h. Target-to-background ratios from planar images averaged 2:1 at 1 h, 3:1 at 4-24 h, and greater than 10:1 at 4 and 24 h for SPECT/CT. Both agents cleared the blood in a biphasic manner; clearance of (123)I-MIP-1072 was approximately 5 times faster. (123)I-MIP-1072 was excreted in the urine, with 54% and 74% present by 24 and 72 h, respectively. In contrast, only 7% and 20% of (123)I-MIP-1095 had been renally excreted by 24 and 72 h, respectively. Estimated absorbed radiation doses were 0.054 versus 0.110 mGy/MBq for the kidneys and 0.024 versus 0.058 mGy/MBq for the liver, for (123)I-MIP-1072 and (123)I-MIP-1095, respectively.

CONCLUSION

(123)I-MIP-1072 and (123)I-MIP-1095 detect lesions in soft tissue, bone, and the prostate gland at as early as 1-4 h. These novel radiolabeled small molecules have excellent pharmacokinetic and pharmacodynamic profiles and warrant further development as diagnostic and potentially when labeled with (131)I therapeutic radiopharmaceuticals.

Utility of GATA3 immunohistochemistry in differentiating urothelial carcinoma from prostate adenocarcinoma and squamous cell carcinomas of the uterine cervix, anus, and lung

Distinguishing invasive high-grade urothelial carcinoma (UC) from other carcinomas occurring in the genitourinary tract may be difficult. The differential diagnosis includes high-grade prostatic adenocarcinoma, spread from an anal squamous cell carcinoma (SCC), or spread from a uterine cervical SCC. In terms of metastatic UC, the most common problem is differentiating spread of UC to the lung from a primary pulmonary SCC. Immunohistochemical analysis (IHC) for GATA binding protein 3 (GATA3), thrombomodulin (THROMBO), and uroplakin III was performed on a tissue microarray (TMA) containing 35 cases of invasive high-grade UC. GATA3 IHC was also performed on TMAs containing 38 high-grade (Gleason score ≥8) prostatic adenocarcinomas, representative tissue sections from 15 invasive anal SCCs, representative tissue sections from 19 invasive cervical SCCs, and TMAs with 12 invasive cervical carcinomas of the cervix [SCC (n=10), SCC with neuroendocrine features (n=1), and adenosquamous carcinoma (n=1)]. In addition, GATA3 IHC was performed on representative tissue sections from 15 pulmonary UC metastases and a TMA with 25 SCCs of the lung and 5 pulmonary non-small cell carcinomas with squamous features. GATA3, THROMBO, and uroplakin III were positive in 28 (80%), 22 (63%), and 21 (60%) cases of high-grade UC, respectively. All cases of GATA3-positive staining were nonfocal; 25 (89%) cases demonstrated moderate to strong staining, and 3 (11%) demonstrated weak staining. Of the 7 cases that failed to express GATA3, 5 were positive for THROMBO and/or uroplakin III, whereas 2 were negative for all 3 markers. None of the 38 high-grade prostatic adenocarcinomas was positive for GATA3. Weak GATA3 staining was present in occasional basal cells of benign prostate glands, in a few benign atrophic glands, and in urothelial metaplasia. Of the 15 cases of anal SCCs, 2 (7%) cases showed focal weak staining, and 1 (3%) showed focal moderate staining. Weak staining was also rarely observed in the benign anal squamous epithelium. Of the 31 uterine cervical carcinomas, 6 (19%) showed weak GATA3 staining (3 nonfocal and 3 focal), and 2 (6%) demonstrated focal moderate staining. Twelve (80%) of the metastatic UCs to the lung were positive for GATA3, with 11 cases showing diffuse moderate or strong staining and 1 case showing focal moderate staining. None of the pulmonary SCCs or non-small cell carcinomas with squamous features was GATA3 positive. GATA3 IHC is a sensitive marker for UC, and positive staining in UC is typically nonfocal and moderate or strong in intensity. GATA3 is also highly specific in excluding high-grade prostate adenocarcinoma. Although some cervical and anal SCCs can be GATA3 positive, unlike in UC, staining is more commonly focal and weak. GATA3 is also a useful maker when diagnosing metastatic UC to the lung.

Immunohistochemical profile to distinguish urothelial from squamous differentiation in carcinomas of urothelial tract

Urothelial neoplasms with squamous morphology raise the differential diagnosis between pure primary squamous cell carcinoma, urothelial carcinoma with squamous differentiation and secondary involvement by squamous cell carcinoma, for example, from uterine cervix. Accurate identification between these entities is critical due to differing prognosis and therapeutic strategies. We evaluated the utility of an immunohistochemical panel of 3 urothelial-associated antibodies (uroplakin III, S100P, and GATA3) and two squamous-associated antibodies (CK14 and desmoglein-3) in 50 primary urothelial neoplasms: 15 pure urothelial carcinomas, 12 pure squamous cell carcinomas and 23 urothelial carcinomas with squamous differentiation. Squamous differentiation was defined by intercellular bridges or evidence of keratinization. Pure squamous cell carcinomas were positive for CK14 (100%) and desmoglein-3 (75%), negative for GATA3 and uroplakin III; one case was S100P positive (9%). Pure urothelial carcinomas had an opposite pattern and were positive for S100P (93%), GATA3 (93%), and uroplakin III (67%) and were negative for desmoglein-3; CK 14 was positive in 27% of cases; 74% of urothelial carcinomas with squamous differentiation had expression of urothelial and squamous associated markers (S100P, 83%; GATA3, 35%; uroplakin III, 13%; CK14, 87%; and desmoglein-3, 70%), although reactivity for individual markers within some tumors did not always correspond with morphologic differentiation. Of the remaining 26%, 4 showed an overall "squamous" immunoprofile, whereas 2 cases showed a "urothelial" immunoprofile. Our study showed that a panel of five antibodies identifies squamous and urothelial differentiation in most instances suggesting potential diagnostic utility.

CK5, CK5/6, and double-stains CK7/CK5 and p53/CK5 discriminate in situ vs invasive urothelial cancer in the prostate

For primary bladder tumors, distinguishing urothelial carcinoma (UC) invading the fibromuscular stroma of the prostate (pT4a) from in situ UC involving prostatic ducts can be difficult. Immunohistochemical markers (cytokeratin [CK]5/6, CK5, CK7, CK20, p53, p63, high-molecular-weight keratin [HMWK], androgen receptor, prostate-specific antigen [PSA], prostate specific acid phosphatase [PSAP], laminin, CD44s, CD141) were assessed for their usefulness in determining depth of UC invasion in the prostate. In cystoprostatectomy specimens containing in situ UC in prostatic ducts, both CK5/6 and CK5 clearly differentiated prostatic basal cells from in situ UC. The remaining markers were not effective in determining depth of tumor invasion. Double-stain combinations CK7/CK5 and p53/CK5 were performed and robustly color contrasted in situ tumor from surrounding basal cells. The use of CK5/6, CK5, CK7/CK5, or p53/CK5 is recommended to assist in determining the depth of UC invasion in the prostate when histologic findings are equivocal.

Differentiating rectal carcinoma by an immunohistological analysis of carcinomas of pelvic organs based on the NCBI Literature Survey and the Human Protein Atlas database

The treatments and prognoses of pelvic organ carcinomas differ, depending on whether the primary tumor originated in the rectum, urinary bladder, prostate, ovary, or uterus; therefore, it is essential to diagnose pathologically the primary origin and stages of these tumors. To establish the panels of immunohistochemical markers for differential diagnosis, we reviewed 91 of the NCBI articles on these topics and found that the results correlated closely with those of the public protein database, the Human Protein Atlas. The results revealed the panels of immunohistochemical markers for the differential diagnosis of rectal adenocarcinoma, in which [+] designates positivity in rectal adenocarcinoma and [-] designates negativity in rectal adenocarcinoma: from bladder adenocarcinoma, CDX2[+], VIL1[+], KRT7[-], THBD[-] and UPK3A[-]; from prostate adenocarcinoma, CDX2[+], VIL1[+], CEACAM5[+], KLK3(PSA)[-], ACPP(PAP)[-] and SLC45A3(prostein)[-]; and from ovarian mucinous adenocarcinoma, CEACAM5[+], VIL1[+], CDX2[+], KRT7[-] and MUC5AC[-]. The panels of markers distinguishing ovarian serous adenocarcinoma, cervical carcinoma, and endometrial adenocarcinoma were also represented. Such a comprehensive review on the differential diagnosis of carcinomas of pelvic organs has not been reported before. Thus, much information has been accumulated in public databases to provide an invaluable resource for clinicians and researchers.

Integration of regulatory networks by NKX3-1 promotes androgen-dependent prostate cancer survival

The NKX3-1 gene is a homeobox gene required for prostate tumor progression, but how it functions is unclear. Here, using chromatin immunoprecipitation coupled to massively parallel sequencing (ChIP-seq) we showed that NKX3-1 colocalizes with the androgen receptor (AR) across the prostate cancer genome. We uncovered two distinct mechanisms by which NKX3-1 controls the AR transcriptional network in prostate cancer. First, NKX3-1 and AR directly regulate each other in a feed-forward regulatory loop. Second, NKX3-1 collaborates with AR and FoxA1 to mediate genes in advanced and recurrent prostate carcinoma. NKX3-1- and AR-coregulated genes include those found in the "protein trafficking" process, which integrates oncogenic signaling pathways. Moreover, we demonstrate that NKX3-1, AR, and FoxA1 promote prostate cancer cell survival by directly upregulating RAB3B, a member of the RAB GTPase family. Finally, we show that RAB3B is overexpressed in prostate cancer patients, suggesting that RAB3B together with AR, FoxA1, and NKX3-1 are important regulators of prostate cancer progression. Collectively, our work highlights a novel hierarchical transcriptional regulatory network between NKX3-1, AR, and the RAB GTPase signaling pathway that is critical for the genetic-molecular-phenotypic paradigm in androgen-dependent prostate cancer.

Folate hydrolase (prostate-specific membrane [corrected] antigen) 1 expression in bladder cancer subtypes and associated tumor neovasculature

Folate hydrolase (prostate-specific antigen) 1 (FH(PSA)1), also known as prostate-specific membrane antigen (PSMA), is a transmembrane receptor expressed on prostate cancer cells that correlates with a more aggressive phenotype. Recent studies have demonstrated FH(PSA)1 expression in numerous benign and malignant tissue types, as well as the malignant neovasculature. As FH(PSA)1 represents a diagnostic immunomarker for prostate cancer, we explored its expression pattern in various subtypes of bladder cancer. Immunohistochemical analysis (IHC) of FH(PSA)1 was performed using tissue microarrays constructed from 167 bladder cancers, including 96 urothelial carcinomas (UCCs), 37 squamous cell carcinomas, 17 adenocarcinomas and 17 small cell carcinomas. We used a FH(PSA)1 monoclonal antibody obtained from Dako (clone 3E6, dilution 1:100), which recognizes the epitope present in the 57-134 amino acid region of the extracellular portion of the PSMA molecule. Intensity of IHC staining was scored as 0 (no expression) to 3+ (strong expression), with 2-3+ IHC considered a positive result. FH(PSA)1 demonstrated expression in a subset of bladder cancers and was most common in small cell carcinoma (3/17; 18%), with concurrent expression in non-small cell components in a subset of cases (2/6). FH(PSA)1 expression was less frequent in UCC (3/96; 3%) and adenocarcinoma (2/17; 12%). None of the squamous cell carcinomas demonstrated tumor cell expression of FH(PSA)1. However, all bladder cancers examined expressed FH(PSA)1 in the tumor vasculature, suggesting a potential role for this molecule in mediating new vessel ingrowth. FH(PSA)1 may occasionally be expressed in various subtypes of bladder cancer. These findings suggest cautious use of FH(PSA)1 as a diagnostic marker for prostatic tissue invading the bladder. The finding of FH(PSA)1 in the bladder cancer neovasculature suggests that this molecule may promote tumor growth and may represent a potential new vascular target in this disease.

Review of small cell carcinomas of the prostate

Small cell carcinoma of the prostate is a rare neoplasm, with only a few series hitherto reported. A little less than half of the cases are associated with conventional acinar adenocarcinoma, which are usually high grade. Although consensus has not been reached, the majority of patients with small cell neuroendocrine carcinoma of the prostate have advanced disease at diagnosis and disproportionally low PSA levels compared to patients with conventional acinar adenocarcinoma. Treatment consists mainly of chemotherapy associated with surgery. Radiation therapy is reserved for selected cases. This study reviews the most up-to-date information on small cell carcinomas of the prostate.

Diagnostic utility of p63/P501S double sequential immunohistochemical staining in differentiating urothelial carcinoma from prostate carcinoma

Background

Distinguishing urothelial carcinoma (UC) from prostate carcinoma (PC) is important due to potential therapeutic and prognostic implications. However, this can be a diagnostic challenge when there is limited tissue and in poorly differentiated tumors. We evaluated the diagnostic utility of a dual immunohistochemical stain comprising p63 and P501S (prostein), applied sequentially on a single slide and visualized by double chromogen reaction, in differentiating these two cancers. Thus far, there have been no previous studies assessing the diagnostic utility of p63 and P501S combined together as a dual immunostain in distinguishing between these two cancers.

Methods

p63/P501S dual-color sequential immunohistochemical staining was performed on archival material from 132 patients with high-grade UC and 23 patients with PC, and evaluated for p63 (brown nuclear) and P501S (red cytoplasmic) expression. Both the staining intensity and percentage of positive tumor cells were assessed.

Results

p63 was positive in 119/132 of UC and negative in PC. P501S was positive in 22/23 of PC and negative in UC. The p63+/P501S- immunoprofile had 90% sensitivity and 100% specificity for UC. The p63-/P501S+ immunoprofile had 96% sensitivity and 100% specificity for PC.

Conclusion

Our results indicate that double sequential immunohistochemical staining with p63 and P501S is highly specific and can be a useful tool in distinguishing UC from PC especially when there is limited diagnostic tissue as it can be performed on a single slide.

Clinical utility of immunohistochemistry in the diagnoses of urinary bladder neoplasia

Urothelial carcinomas demonstrate diverse morphologic and immunologic features that frequently lead to diagnostic challenges. Recent advances have identified a number of immunohistochemical stains that, when used in the context of a panel, can be a valuable tool in properly classifying primary urothelial carcinoma and carcinomas secondarily involving the urinary bladder. In addition, new biomarkers prove helpful in the staging of bladder carcinoma. In this article, we review the clinical utility of immunohistochemistry in a series of diagnostic scenarios, including flat urothelial lesions with atypia, rare variants of urothelial carcinoma, primary adenocarcinoma versus secondary colorectal tumors, distinguishing prostate from urothelial carcinoma, and the utility of smoothelin in staging bladder carcinoma. Emphasis is placed on panels of commonly used biomarkers to establish diagnoses.

Immunohistochemical diagnosis of renal neoplasms

CONTEXT

Histologic diagnosis of renal neoplasm is usually straightforward by routine light microscopy. However, immunomarkers may be essential in several contexts, including differentiating renal from nonrenal neoplasms, subtyping of renal cell carcinoma (RCC), and diagnosing rare types of renal neoplasms or metastatic RCC in small biopsy specimens.

OBJECTIVE

To provide a comprehensive review of the diagnostic utility of immunomarkers for renal neoplasms.

DESIGN

This review is based on published literature and personal experience.

CONCLUSIONS

The following markers may have diagnostic utility in various diagnostic contexts: cytokeratins, vimentin, α-methylacyl coenzyme A racemase, carbonic anhydrase IX, PAX2, PAX8, RCC marker, CD10, E-cadherin, kidney-specific cadherin, parvalbumin, claudin-7, claudin-8, S100A1, CD82, CD117, TFE3, thrombomodulin, uroplakin III, p63, and S100P. Cytokeratins are uniformly expressed by RCC, albeit in a somewhat limited amount in some subtypes, requiring broad-spectrum anti-CK antibodies, including both low- and high-molecular-weight cytokeratins. PAX2 and PAX8 are sensitive and relatively specific markers for renal neoplasm, regardless of subtype. CD10 and RCC marker are sensitive to renal cell neoplasms derived from proximal tubules, including clear cell and papillary RCCs. Kidney-specific cadherin, parvalbumin, claudin-7, and claudin-8 are sensitive markers for renal neoplasms from distal portions of the nephron, including chromophobe RCC and oncocytoma. CK7 and α-methylacyl coenzyme A racemase are sensitive markers for papillary RCC; TFE3 expression is essential in confirming the diagnosis of Xp11 translocation RCC. The potentially difficult differential diagnosis between chromophobe RCC and oncocytoma may be facilitated by S100A1 and CD82. Thrombomodulin, uroplakin III, p63, and S100P are useful markers for urothelial carcinoma. Together with high-molecular-weight cytokeratins, PAX2, and PAX8, they can help differentiate renal pelvic urothelial carcinoma from collecting duct RCC. A sensitive marker for sarcomatoid RCC is still not available. Immunomarkers are most often used for diagnosing metastatic RCC. Compared with primary RCC, expression of the above-mentioned markers is often less frequent and less diffuse in the metastatic setting. Recognizing the variable sensitivity and specificity of these markers, it is important to include at least CD10, RCC marker, PAX2, and PAX8 in the diagnostic panel.

GAD1 is a biomarker for benign and malignant prostatic tissue

OBJECTIVE

Tissue-specific markers are useful for identification of tumour type in advanced cancers of unknown origin. This study investigated the expression of glutamate decarboxylase 1 (GAD1) in prostate and control tissue compared with the established prostate-specific markers prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA).

MATERIAL AND METHODS

A tissue microarray was constructed of 36 prostate adenocarcinomas, eight benign prostate samples and benign and malignant control tissues from urinary bladder, lung and rectum. Immunohistochemistry for GAD1, PSA and PSMA was performed. The products of staining intensity and extent were analysed. The GAD1 antibody was validated by Western blot. Real-time polymerase chain reaction (RT-PCR) was performed on malignant and benign samples from each tissue type.

RESULTS

GAD1 and PSA immunostains were significantly stronger in malignant and benign prostatic tissue than in controls. PSMA was stronger in prostate cancer than in urothelial and rectal cancer but had a lower specificity than GAD1 and PSA. GAD1 expression decreased with increasing Gleason score. RT-PCR confirmed the presence of mRNA for GAD1, PSA and PSMA in prostate samples.

CONCLUSION

GAD1 is expressed in benign and malignant prostatic tissue and may serve as a highly prostate-specific tissue biomarker.

A cribriform urothelial neoplasm of the renal pelvis: an adenoid cysticlike variant of inverted urothelial papilloma or florid ureteritis cystica?

Tumors with cribriform appearance, similar to that of salivary gland adenoid cystic carcinoma, have been described at various anatomic sites. We present an unusual polypoid tumor, discovered incidentally, in the renal pelvis of an elderly man. The mass displayed a prominent cribriform architecture, akin to adenoid cystic carcinoma with an immunophenotype that supported a urothelial origin. Because of its lack of significant invasive growth and other adverse morphologic features, this lesion will likely behave in a banal fashion. This cribriform urothelial neoplasm of the renal pelvis may, in fact, represent a variant of an inverted urothelial neoplasm with a prominent cystic component or florid ureteritis cystica. It is important for pathologists to recognize this growth pattern as a possible variant of urothelial tumors.

NKX3.1 as a marker of prostatic origin in metastatic tumors

NKX3.1 is a prostatic tumor suppressor gene located on chromosome 8p. Although most studies have shown that staining for NKX3.1 protein is positive in the majority of primary prostatic adenocarcinomas, it has been shown to be downregulated in many high-grade prostate cancers, and completely lost in the majority of metastatic prostate cancers (eg, in 65% to 78% of lesions). A recent study showed that NKX3.1 staining with a novel antibody was highly sensitive and specific for high-grade prostatic adenocarcinoma when compared with high-grade urothelial carcinoma. This raised the question that this antibody may perform better than earlier used antibodies in metastatic prostate tumors. However, the sensitivity and specificity for prostate carcinomas for this antibody in metastatic lesions was not determined. Although prostate-specific antigen (PSA) and prostatic-specific acid phosphatase (PSAP) are excellent tissue markers of prostate cancer, at times they may be expressed at low levels, focally, or not at all in poorly differentiated primary and metastatic prostatic adenocarcinomas. The purpose of this study was to determine the performance of NKX3.1 as a marker of metastatic adenocarcinoma of prostatic origin. Immunohistochemical staining against NKX3.1, PSA, and PSAP was carried out on a tissue microarray (TMA) (0.6-mm tissue cores) of hormone naïve metastatic prostate adenocarcinoma specimens from lymph nodes, bone, and soft tissue. To determine the specificity of NKX3.1 for prostatic adenocarcinoma, we used TMAs that contained cancers from various sites including the urinary bladder, breast, colon, salivary gland, stomach, pancreas, thyroid, and central nervous system, and standard paraffin sections of cancers from other sites including the adrenal cortex, kidney, liver, lung, and testis. Overall 349 nonprostatic tumors were evaluated. Any nuclear staining for NKX3.1 was considered positive and the percentage of cells with nuclear staining and their mean intensity level were assessed visually. Sensitivity was calculated by considering a case positive if any TMA core was positive. The sensitivity for identifying metastatic prostatic adenocarcinomas overall was 98.6% (68/69 cases positive) for NKX3.1, 94.2% (65/69 cores positive) for PSA, and 98.6% (68/69 cores positive) for PSAP. The specificity of NKX3.1 was 99.7% (1/349 nonprostatic tumors positive). The sole positive nonprostatic cancer case was an invasive lobular carcinoma of the breast. NKX3.1 seems to be a highly sensitive and specific tissue marker of metastatic prostatic adenocarcinoma. In the appropriate clinical setting, the addition of IHC staining for NKX3.1, along with other prostate-restricted markers, may prove to be a valuable adjunct to definitively determine prostatic origin in poorly differentiated metastatic carcinomas.

Concomitant tumor and minor histocompatibility antigen-specific immunity initiate rejection and maintain remission from established spontaneous solid tumors

Nonmyeloablative hematopoietic cell transplantation can cure patients with hematologic malignancies but has reported limited success against solid tumors. This is possibly because of profound peripheral tolerance mechanisms and/or suboptimal tumor recognition by effector T lymphocytes. We report that in mice developing spontaneous prostate cancer, nonmyeloablative minor histocompatibility mismatched hematopoietic stem cell transplantation, and donor lymphocyte infusion of unmanipulated lymphocytes combined with posttransplant tumor-specific vaccination circumvents tumor-specific tolerance, allowing acute tumor rejection and the establishment of protective immunosurveillance. Although donor-derived tumor-specific T cells readily differentiated into effector cells and infiltrated the tumor soon after infusion, they were alone insufficient for tumor eradication, which instead required the concomitance of minor histocompatibiltiy antigen-specific CD8(+) T-cell responses. The establishment of protective immunosurveillance was best induced by posttransplant tumor-specific vaccination. Hence, these results provide the proof of principle that tumor-specific T-cell responses have to be harnessed together with minor histocompatibility responses and sustained by posttransplant tumor-specific vaccination to improve the efficacy of allotransplantion for the cure of solid tumors.

MYC overexpression induces prostatic intraepithelial neoplasia and loss of Nkx3.1 in mouse luminal epithelial cells

Lo-MYC and Hi-MYC mice develop prostatic intraepithelial neoplasia (PIN) and prostatic adenocarcinoma as a result of MYC overexpression in the mouse prostate. However, prior studies have not determined precisely when, and in which cell types, MYC is induced. Using immunohistochemistry (IHC) to localize MYC expression in Lo-MYC transgenic mice, we show that morphological and molecular alterations characteristic of high grade PIN arise in luminal epithelial cells as soon as MYC overexpression is detected. These changes include increased nuclear and nucleolar size and large scale chromatin remodeling. Mouse PIN cells retained a columnar architecture and abundant cytoplasm and appeared as either a single layer of neoplastic cells or as pseudo-stratified/multilayered structures with open glandular lumina-features highly analogous to human high grade PIN. Also using IHC, we show that the onset of MYC overexpression and PIN development coincided precisely with decreased expression of the homeodomain transcription factor and tumor suppressor, Nkx3.1. Virtually all normal appearing prostate luminal cells expressed high levels of Nkx3.1, but all cells expressing MYC in PIN lesions showed marked reductions in Nkx3.1, implicating MYC as a key factor that represses Nkx3.1 in PIN lesions. To determine the effects of less pronounced overexpression of MYC we generated a new line of mice expressing MYC in the prostate under the transcriptional control of the mouse Nkx3.1 control region. These "Super-Lo-MYC" mice also developed PIN, albeit a less aggressive form. We also identified a histologically defined intermediate step in the progression of mouse PIN into invasive adenocarcinoma. These lesions are characterized by a loss of cell polarity, multi-layering, and cribriform formation, and by a "paradoxical" increase in Nkx3.1 protein. Similar histopathological changes occurred in Hi-MYC mice, albeit with accelerated kinetics. Our results using IHC provide novel insights that support the contention that MYC overexpression is sufficient to transform prostate luminal epithelial cells into PIN cells in vivo. We also identified a novel histopathologically identifiable intermediate step prior to invasion that should facilitate studies of molecular pathway alterations occurring during early progression of prostatic adenocarcinomas.

Cancer of unknown primary finally revealed to be a metastatic prostate cancer: a case report

The vast majority of patients with metastatic prostate cancer present with bone metastases and high prostate specific antigen (PSA) level. Rarely, prostate cancer can develop in patients with normal PSA level. Here, we report a patient who presented with a periureteral tumor of unknown primary site that was confirmed as prostate adenocarcinoma after three years with using specific immunohistochemical examination. A 64-year old man was admitted to our hospital with left flank pain associated with masses on the left pelvic cavity with left hydronephrosis. All tumor markers including CEA, CA19-9, and PSA were within the normal range. After an exploratory mass excision and left nephrectomy, the pelvic mass was diagnosed as poorly differentiated carcinoma without specific positive immunohistochemical markers. At that time, we treated him as having a cancer of unknown primary site. After approximately three years later, he revisited the hospital with a complaint of right shoulder pain. A right scapular mass was newly detected with a high serum PSA level (101.7 ng/ml). Tissues from the scapular mass and prostate revealed prostate cancer with positive immunoreactivity for P504S, a new prostate cancer-specific gene. The histological findings were the same as the previous pelvic mass; however, positive staining for PSA was observed only in the prostate mass. This case demonstrates a patient with prostate cancer and negative serological test and tissue staining that turned out to be positive during progression. We suggest the usefulness of newly developed immunohistochemical markers such as P504S to determine the specific primary site of metastatic poorly differentiated adenocarcinoma in men.

Secondary neoplasms of the urinary system and male genital organs

BACKGROUND AND AIMS

In this review we discuss those secondary tumours involving the urinary system and male genital organs that can pose differential diagnostic difficulties with primary lesions, and highlight morphological and ancillary features that could be helpful in reaching a proper assignment of primary origin.

MATERIALS AND METHODS

Based on MEDLINE database searches all reports of secondary tumours involving the urinary system (kidney and bladder) and male genital organs (prostate, testis and penis) were examined.

RESULTS AND DISCUSSION

Involvement by a secondary tumour occurs either as a metastasis or by direct extension. Among non-genitourinary primary sites, colorectal, pulmonary, skin (melanoma) and breast are the most common contributors. Secondary spread from a genitourinary site primary tumour to another genitourinary organ occurs most frequently between the prostate and urinary bladder, given the intimate topographic proximity of the two. The prognosis is very poor, as the secondary tumour usually occurs in patients with carcinoma in the late stages. Few secondary tumours have distinctive histological and immunohistochemical features, making it difficult to make the appropriate diagnosis. Hence, knowledge of the history and clinical setting are particularly important in these cases.

CONCLUSION

The urinary system and male genital organs are not common sites for secondary tumours. They often go either undiagnosed or misdiagnosed in the clinical follow-up of patients with cancer. Accurate diagnosis is essential because of differing therapeutic approaches compared with a primary neoplasm.

Histological variants of urothelial carcinoma: diagnostic, therapeutic and prognostic implications

It is well established that invasive urothelial carcinoma, involving the urinary bladder and renal pelvis, has marked propensity for divergent differentiation. In recent years, several 'variant' morphologies have been described and most have been recognized in the 2004 World Health Organization Classification. These histological variants of urothelial carcinoma have clinical significance at various levels, including diagnostic, that is, awareness of the morphological variant is essential in order to avoid diagnostic misinterpretations; prognostic for patient risk stratification; and therapeutic, where a diagnostic assignment of a particular variant may be associated with the administration of a therapy distinctive from that used in conventional invasive urothelial carcinoma. The diagnoses of micropapillary urothelial carcinoma, small-cell carcinoma, lymphoepithelioma-like carcinoma and sarcomatoid carcinoma are prime examples where treatment protocols may be different than the usual muscle-invasive bladder cancer. This review discusses the variants of urothelial carcinoma, outlining for each the diagnostic features, differential diagnostic considerations and the clinical significance.

Pathologic evaluation of unknown primary cancer

The pathologic approach to metastases of unknown primary cancer (UPC) is stepwise and uses the clinical context, morphology, and, where necessary, immunohistochemistry (IHC). This review covers the initial approach to a UPC biopsy; the diagnosis of malignancy and broad tumor typing into carcinoma, melanoma, lymphoma, or sarcoma; and further subtyping of carcinoma into germ cell (broadly included), squamous, neuroendocrine, and solid organ including liver and renal, and adenocarcinomas. Finally, for adenocarcinoma, the prediction of primary tumor site, including lung, pancreas, stomach, colon, ovary, prostate, and breast, is discussed. For each tumor type, the morphologic features are presented alongside established useful IHC markers, with a description of their staining patterns and common diagnostic dilemmas. Optimal tissue handling and IHC interpretation, quality assurance, and limitations also are discussed. The target readership is oncologists, but other clinicians and trainee pathologists also may find the content of use.

Utility of diagnostic and prognostic markers in urothelial carcinoma of the bladder

Urothelial carcinoma (UCC) of the bladder demonstrates diverse morphologic features, often leading to diagnostic challenges in the discrimination between UCC and benign mimickers of neoplasia, and between primary UCC and secondary neoplasms involving the bladder. In situ lesions also provide diagnostic difficulty in some instances, most prominently in the distinction between normal, reactive urothelium and flat urothelial carcinoma in situ. The use of ancillary techniques, including panels of immunohistochemical markers, in distinguishing these entities has aided not only in the diagnosis of UCC, but has also provided insight into the molecular pathogenesis and prognostic value of numerous molecular pathways in UCC. This review focuses on some of the more commonly encountered biomarkers in UCC and their role in addressing key diagnostic and prognostic issues in this disease process.

Molecular alterations in prostate cancer as diagnostic, prognostic, and therapeutic targets

Prostatic adenocarcinoma is extremely common in Western nations, representing the second leading cause of cancer death in American men. The recent application of increasingly sophisticated molecular approaches to the study of prostate cancer in this "postgenomic" era has resulted in a rapid increase in the identification of somatic genome alterations and germline heritable risk factors in this disease. These findings are leading to a new understanding of the pathogenesis of prostate cancer and to the generation of new targets for diagnosis, prognosis, and prediction of therapeutic response. Although we are still in the very early phase of clinical development, some of the molecular alterations identified in prostate cancer are being translated into clinical practice. The purpose of this review is to update the practicing surgical pathologist, and residents-in-training in pathology, regarding recent findings in the molecular pathobiology of prostate cancer. We will highlight some of the somatic molecular alterations associated with prostate cancer development and progression, with a focus on newer discoveries. In addition, recent studies in which new molecular diagnostic approaches have been applied in the clinic will be discussed.

Best practice in diagnostic immunohistochemistry: prostate carcinoma and its mimics in needle core biopsies

CONTEXT

The unrelenting challenge encountered when differentiating limited-volume prostate carcinoma and sometimes subtle variants from its many morphologic mimics has increased the use of ancillary immunohistochemistry in routine prostate needle biopsies. The availability of prostate cancer-associated and basal cell-associated markers has been an invaluable addition to diagnostic surgical pathology.

OBJECTIVE

To review commonly used immunohistochemical stains, including innovative combinations, for confirmation or differential diagnosis of prostate carcinoma, and to propose appropriately constructed panels using morphologic patterns in prostate needle biopsies.

DATA SOURCES

These best practices are based on our experience with routine and consultative case sign-outs and on a review of the published English-language literature from 1987 through 2008.

CONCLUSIONS

Basal cell-associated markers p63, high-molecular-weight cytokeratin 34 beta E12, cytokeratin 5/6 or a cocktail containing p63 and high-molecular-weight cytokeratin 34 beta E12 or cytokeratin 5/6 and prostate carcinoma-specific marker alpha-methylacyl coenzyme A (coA) racemase alone or in combination are useful adjuncts in confirming prostatic carcinoma that either lacks diagnostic, qualitative or quantitative features or that has an unusual morphologic pattern (eg, atrophic, pseudohyperplastic) or is in the setting of prior treatment. The combination of alpha-methylacyl coA racemase positivity with negative staining for basal cell-associated markers supports a malignant diagnosis in the appropriate morphologic context. Dual chromogen basal cell- associated markers (p63 [nuclear] and high-molecular-weight cytokeratin 34 beta E12/cytokeratin 5/6 [cytoplasmic]) and alpha-methylacyl coA racemase in an antibody cocktail provide greater sensitivity for the basal cell layer, easing evaluation and minimizing loss of representation of the focal area interest because the staining is performed on one slide. In the posttreatment setting, pancytokeratin facilitates detection of subtle-treated cancer cells. Prostate-specific antigen and prostatic acid phosphatase markers are helpful in excluding secondary malignancies involving the prostate, such as urothelial carcinoma, and occasionally in excluding nonprostatic benign mimickers, such as nephrogenic adenoma, mesonephric gland hyperplasia, and Cowper glands. There is no role for ordering immunohistochemistry prospectively in all cases of prostatic needle biopsies.

The significance of monoamine oxidase-A expression in high grade prostate cancer

PURPOSE

Gleason grade 4/5 prostate cancer is a determinant for recurrence following radical prostatectomy. Monoamine oxidase-A is over expressed in grade 4/5 compared to grade 3 cancer. Monoamine oxidase-A is also expressed by normal basal cells and in vitro studies suggest that its function is to repress secretory differentiation. Therefore, monoamine oxidase-A in grade 4/5 cancer might reflect dedifferentiation to a basal cell-like phenotype. We investigated whether monoamine oxidase-A expression correlates with another basal cell protein, CD44, in high grade cancer and whether either is associated with an aggressive phenotype.

MATERIALS AND METHODS

A total of 133 grade 4/5 archival cancers from a cohort previously used to evaluate the prognostic significance of histomorphological variables were scored for monoamine oxidase-A and CD44 immunohistochemical labeling. Spearman rank correlations of the proteins, and histomorphological and clinical variables were determined. The univariate and multivariate value of each variable as a determinant of biochemical recurrence was assessed by logistic regression.

RESULTS

Monoamine oxidase-A expression correlated with CD44. Neither was prognostic for biochemical recurrence. However, monoamine oxidase-A expression positively correlated with preoperative serum prostate specific antigen and the percent of grade 4/5 cancer.

CONCLUSIONS

Concurrent expression of monoamine oxidase-A and CD44 suggests that grade 4/5 cancer may be basal cell-like in nature, despite the absence of other classic basal cell biomarkers such as cytokeratins 5 and 14, and p63. The correlation of monoamine oxidase-A expression with prostate specific antigen and the percent of grade 4/5 cancer suggests that monoamine oxidase-A may contribute to growth of high grade cancer and that antidepressant drugs that target monoamine oxidase-A may have applications in treating prostate cancer.