Caspase-3/CPP32 immunoreactivity and its correlation with frequency of apoptotic bodies in human prostatic carcinomas and benign nodular hyperplasias

AIMS: Apoptosis is mediated by apoptosis-specific genes, certain oncogenes and tumour suppressor genes. Caspase-3, a group of cystein proteases, is involved in the induction of apoptosis and has been considered to correlate with apoptosis. The aim of this study was to determine whether caspase-3 is expressed in prostatic carcinoma and benign prostatic hyperplasia, and correlated with the apoptosis. METHODS AND RESULTS: We studied the apoptotic index and caspase-3 immunoreactivity in 40 cases of benign nodular hyperplasia (BPH) and 40 cases of prostate carcinoma (PCA) by in-situ labelling and immunohistochemistry. The mean number of apoptotic bodies in cases with BPH was not significantly different from cases with PCA I (Gleason score 2-4), but samples from patients with PCA II (Gleason score 5-7) and PCA III (Gleason score 8-10) showed a significantly higher apoptotic number than cases with BPH. Positive staining for caspase-3 was seen in 42.5% (17/40) of the BPH, and 27.5% (11/40) of the PCA: PCA I was 41.7% (5/12), PCA II 14.3% (2/14) and PCA III was 28.6% (4/14). CONCLUSIONS: Based on our results, the number of apoptotic bodies was not correlated with the caspase-3 expression and there was no relationship between caspase-3 expression and Gleason score. However, the number of apoptotic bodies was significantly higher in cases with intermediate (Gleason score 5-7) and high-grade (Gleason score 8-10) PCAs than cases with BPH and low-grade PCAs (Gleason score 2-4).     

Alpha-methylacyl-CoA racemase (P504S) expression in evolving carcinomas within benign prostatic hyperplasia and in cancers of the transition zone

Carcinomas of the transition zone (TZ) constitute approximately 20% of all prostate cancers. The TZ is the site of origin of grade 1 and grade 2 cancers, the most well-differentiated of the Gleason grade tumors, as well as for benign prostatic hyperplasia (BPH). In this regard, grade 1 carcinoma has architectural features that closely mimic gland-rich BPH nodules. Although a relationship between cancers arising in this zone and BPH has been suspected, such an association remains undefined. To gain insight into the origin, development, and progression of cancers arising in the TZ, we used a highly specific rabbit monoclonal antibody (P504S) directed against alpha-methylacyl-CoA racemase (AMACR) to study the expression of the enzyme in 25 cases of evolving and fully developed carcinomas of this zone. AMACR has been proposed as a new molecular marker for prostate cancer, because the enzyme is reportedly overexpressed in high-grade dysplasias, also termed prostatic intraepithelial neoplasia, a purported precursor of prostatic carcinoma, and in all grades of prostatic carcinoma of the peripheral zone. Using P504S, P63, or antikeratin 34beta E12 antibodies, we found it possible to define areas of transition from hyperplasia to carcinoma in 6 BPH nodules. In 3 other cancer-containing BPH nodules, staining for AMCAR was observed in benign hyperplastic glands that were juxtaposed to carcinoma. Enzyme expression was also evident in 5 additional cases in which BPH was found adjacent to cancer. In contrast; AMACR was not visualized in any other BPH nodules that we studied. Thus, using the enzyme as a marker, we document for the first time that some carcinomas of the TZ arise from an AMCAR-positive transition lesion within a subset of BPH nodules. Moreover, the finding of enhanced AMACR expression in benign glands within cancer-containing nodules as well as in BPH lesions adjacent to carcinoma suggests that in some cases, up-regulation of the enzyme may precede morphological evidence of neoplastic transformation. AMACR was lightly expressed in transition lesions and grade 1 carcinomas but more strongly expressed in higher-grade TZ cancers, suggesting that enzyme expression is enhanced with progression in this zone. Because AMACR is involved in the beta oxidation of branched fatty acids and their derivatives, enhanced expression of the enzyme in evolving carcinomas in BPH nodules, as well as its up-regulation in juxtaposed morphologically benign glands and grade 1 carcinomas, suggests that increased utilization of fatty acids may play an important role in carcinoma development and progression in the TZ.     

Detection of prostate cancer by alpha-methylacyl CoA racemase (P504S) in needle biopsy specimens previously reported as negative for malignancy

AIMS : To investigate the possibility of detecting small focal prostatic cancer by alpha-methylacyl CoA racemase (AMACR)/P504S immunohistochemistry on needle biopsy specimens that were previously interpreted as negative for carcinoma on routine haematoxylin and eosin (H&E)-stained sections. METHODS: Prostate needle biopsy specimens (n = 793) previously interpreted as benign prostatic tissue by conventional morphology from 239 patients with prostatic cancer diagnosed in other biopsy cores taken at the same biopsy session were stained with the P504S monoclonal antibody. If a biopsy specimen stained positively, two pathologists independently reviewed the original corresponding H&E-stained sections to establish the malignant diagnosis. RESULTS: Eighty-four of the 793 biopsy specimens showed AMACR immunoreactivity; nine of these (9/793, 1.1%) contained previously unrecognized small focal prostatic carcinoma (Gleason 6, N = 8; Gleason 8, N = 1). Six of nine (67%) carcinomas showed foamy/pseudohyperplastic (N = 3) or atrophic (N = 3) features. Additionally, five biopsy specimens (5/793, 0.6%) with positive AMACR staining that did not meet the criteria for prostatic cancer on the original H&E slides were considered to be atypia. CONCLUSIONS: In this study, we found a 1.1% false-negative rate for carcinoma on routine H&E-stained sections. AMACR immunohistochemical staining has shown the ability to improve detection of small focal prostatic carcinoma that could be missed by conventional histological examination.     

Comparison of annexin II, p63 and alpha-methylacyl-CoA racemase immunoreactivity in prostatic tissue: a tissue microarray study

BACKGROUND: Current ancillary markers for diagnosis in prostate biopsies include p63 and alpha-methylacyl-CoA racemase (AMACR). Annexin II (ANXII), a calcium and phospholipid binding protein, is lost in prostate cancer. AIMS: To investigate ANXII expression in order to assess its utility as a novel diagnostic marker in comparison to p63 and AMACR. METHODS: Using immunohistochemistry on six tissue microarrays, ANXII, p63, and AMACR expression was analysed from 210 radical prostatectomy cases. Staining was evaluated in benign and atrophic glands, high-grade prostatic intraepithelial neoplasia (HGPIN), and prostatic adenocarcinoma. Separate scores were given for ANXII, AMACR and p63 expression. RESULTS: Diffuse cytoplasmic expression of ANXII correlated with p63 reactivity in basal cells. Benign glands were positive for ANXII in 286/292 cores (98%) and negative for AMACR in all 292 cores. HGPIN showed heterogeneous expression of AMACR and ANXII. A significantly larger proportion of HGPIN glands were correctly identified as ANXII negative than as positive for AMACR. ANXII loss in prostate cancer was found in 282/320 cores (88%) and correlated with positive AMACR expression (272/320 cores, 85%), which was not statistically significant. There was no statistically significant correlation between ANXII scores and the clinical parameters examined. CONCLUSIONS: Immunohistochemical staining for ANXII is a consistent and reliable marker of prostatic neoplasia. The findings of this study suggest the potential utility of ANXII as a diagnostic aid in prostate cancer histopathology.     

抗体鸡尾酒AMACR/P63/34βE12在前列腺良恶性病变鉴别诊断中的应用价值

目的:探讨抗体鸡尾酒AMACR/P63/34βE12在前列腺良恶性病变鉴别诊断中的应用价值。方法:收集2001~2005年111例前列腺手术切除标本，其中前列腺腺癌39例，高级别前列腺上皮内瘤（high-grade prostatic intraepithelial neoplasias，HGPIN）29例，非典型性腺瘤样增生（atypical adenomatous hyperplasia, AAH）3例，前列腺结节性增生（benign prostatic hyperplasia, BPH）40例。作抗体鸡尾酒AMACR/P63/34βE12的免疫标记，观察3种抗体在各类病变中的表达情况。结果:39例前列腺腺癌AMACR全部呈阳性，癌巢周围无基底细胞残存（P63/34βE12阴性）。29例高级别前列腺上皮内瘤变，14例（48.3%）腺泡上皮AMACR呈阳性，29例腺泡上皮周围有连续或不连续的基底细胞（P63/34βE12阳性）。3例非典型性腺瘤样增生中2例腺泡上皮AMACR呈弱阳性；3例腺泡上皮周围有较连续的基底细胞（P63/34βE12中度阳性）。40例前列腺结节性增生，腺泡上皮AMACR染色均呈阴性，周围有连续的基底细胞（P63/34βE12强阳性）。结论:鸡尾酒抗体AMACR/P63/34βE12标记前列腺组织，能够同时高特异性和敏感性地检测出前列腺腺癌细胞（或非典型增生的腺泡上皮细胞）和基底细胞，为前列腺腺癌与高级别上皮內瘤变、非典型性腺瘤样增生、前列腺结节性增生的鉴别诊断提供有力的证据。     

Utility of immunohistochemistry for alpha-methylacyl-CoA racemase in distinguishing atrophic prostate cancer from benign atrophy

Small atrophic prostate cancers on needle biopsy are rare and difficult to distinguish from benign atrophy on needle biopsy. We report on a study of 23 needle biopsy specimens with small foci of atrophic prostate cancer from the consult service of one of the authors. In 19 cancer cases the atrophic component was pure; in 4 cases it was dominant with a minor (<5%) nonatrophic cancer component. These atrophic cancers and 16 cases of florid benign atrophy on needle biopsy were examined by immunohistochemistry for alpha-methylacyl-CoA-racemase (AMACR). All cases of cancer and atrophy were verified immunohistochemically with antibodies to basal cells (34betaE12 and p63). AMACR staining were scored as 1+ (5% to 25% of glands expressing AMACR), 2+ (26% to 50% of glands expressing AMACR), or 3+ (>50% of glands expressing AMACR). Positive staining was defined as staining above that of surrounding benign glands. AMACR was expressed in 69.6% of atrophic prostate cancers (3+, 11 cases; 2+, 3 cases; 1+, 2 cases); 30.4% (7 cases) of atrophic prostate cancer exhibited no AMACR expression. In the 4 cases with a few glands of ordinary (nonatrophic) prostate cancer, the nonatrophic cancer demonstrated more intense and a greater extent of AMACR staining. Fourteen cases (87.5%) of benign atrophy showed no AMACR expression. In 2 cases (12.5%) of benign atrophy, background immunostaining made it difficult to assess AMACR expression. We conclude that AMACR immunostaining alone is not sufficiently discriminatory in the differential diagnosis of atrophic prostate cancer versus benign atrophy. Atrophic prostate cancers are not as frequently or as strongly positive as ordinary prostate cancer. Using a panel of immunostains including AMACR, 34betaE12 and p63 (positive AMACR immunostaining along with negative basal cell markers) is recommended in the differentiation of atrophic prostate cancer and benign atrophy.     

Using an AMACR (P504S)/34betaE12/p63 cocktail for the detection of small focal prostate carcinoma in needle biopsy specimens

We assessed the usefulness of immunohistochemical analysis with a 3-antibody cocktail (alpha-methylacyl coenzyme A racemase [AMACR, or P504S], 34betaE12, p63) and a double-chromogen reaction for detection of limited prostate cancer in 138 needle biopsy specimens, including 82 with small foci of prostatic adenocarcinoma and 56 benign prostates. When carcinoma was present, red cytoplasmic granular staining (AMACR) in the malignant glands and cells and dark brown nuclear (p63) and cytoplasmic (34betaE12) staining in basal cells of adjacent nonmalignant glands were found. Of 82 cases of small foci of prostatic adenocarcinoma, 78 (95%) expressed AMACR; all malignant glands were negative for basal cell staining. All benign glands adjacent to malignant glands were recognized easily by basal cell marker positivity and little or no AMACR expression. No benign glands were simultaneously positive for AMACR and negative for basal cell markers (specificity, 100%). There were no differences in intensity and numbers of positive glands with double-chromogen staining compared with using 1-color staining. Our results indicate that immunohistochemistry with a 3-antibody cocktail and double chromogen is a simple and easy assay that can be used as a routine test, which overcomes the problems of studying small lesions in prostate needle biopsies with multiple immunohistochemical stains.     

Overexpression of Pim-1 during progression of prostatic adenocarcinoma

AIMS: Pim-1 is a serine/threonine kinase that has been shown to play an integral role in the development of a number of human cancers, such as haematolymphoid malignancies. Recently, evidence has shown Pim-1 to be important in prostatic carcinogenesis. In order to further our understanding of its role in prostate cancer, we investigated Pim-1 expression in normal, premalignant, and malignant prostate tissue. METHODS: Using immunohistochemistry, Pim-1 expression was analysed in prostate tissue from 120 radical prostatectomy specimens. In each case, Pim-1 staining was evaluated in benign prostatic epithelium, high grade prostatic intraepithelial neoplasia (PIN), and prostatic adenocarcinoma. The number of positively staining cells was estimated, and the intensity of staining was scored on a scale of 0 to 3+. RESULTS: Pim-1 immunoreactivity was identified in 120 cases (100%) of adenocarcinoma, 120 cases (100%) of high grade PIN, and 62 cases (52%) of benign glands. The number of cells staining in benign epithelium (mean 34%) was much lower than that in high grade PIN (mean 80%; p<0.0001) or adenocarcinoma (mean, 84%; p<0.0001). There was no significant difference between high grade PIN and adenocarcinoma in the percentage of cells staining positively for Pim-1 (p = 0.34). The staining intensity for Pim-1 was significantly lower in benign prostatic epithelium than in PIN and adenocarcinoma (p<0.001). There was no statistically significant correlation between the level of Pim-1 expression and Gleason score, patient age, tumour stage, lymph node metastasis, perineural invasion, vascular invasion, surgical margin status, extraprostatic extension, or seminal vesicle invasion. CONCLUSIONS: Pim-1 expression is elevated in PIN and prostatic adenocarcinoma compared with benign prostatic epithelium. This finding suggests that upregulation of Pim-1 may play a role in prostatic neoplasia.     

Overexpression of chromatin assembly factor-1 (CAF-1) p60 is predictive of adverse behaviour of prostatic cancer

Aims:  Prostatic cancer may remain organ-confined indefinitely; in a number of patients, however it gives rise to clinical symptoms and death. The biological behaviour of this tumour mostly remains difficult to predict. A promising tool for diagnosis and prognosis of some human tumours is the chromatin assembly factor-1 (CAF-1), involved in the control of higher order chromatin organization. The aim was to explore the role of CAF-1/p60 protein as a new prognostic marker for prostatic cancer.
Methods and results:  The expression of CAF-1/p60 was evaluated by immunohistochemistry and Western blotting in a selected series of prostatic cancers and in prostatic cancer cell lines. Results were compared with clinicopathological data and outcome of patients. CAF-1/p60 was expressed in all cases, with a linear increase from low-grade tumours (Gleason score <7) to high-grade prostatic cancers (Gleason score >7). By comparing results with follow-up data, a significant association between overexpression of CAF-1/p60 and unfavourable behaviour of prostatic cancer emerged, and its predictive value was independent of classical prognostic factors.
Conclusions:  In our series of cases, overexpression of CAF-1/p60 characterized prostatic cancers with a worse prognosis. CAF-1/p60 has a potential role as a new reliable prognostic biomarker for prostatic cancer.     

Reelin expression in human prostate cancer: a marker of tumor aggressiveness based on correlation with grade.

Reelin is a glycoprotein that plays a critical role in the regulation of neuronal migration during brain development and, since reelin has a role in the control of cell migration, it might represents an important factor in cancer pathology. In this study, 66 surgical specimens of prostate cancer were analyzed for reelin expression by immunohistochemical method. The reelin expression was correlated with Gleason score and individual Gleason patterns. Reelin expression was found in 39% prostate cancers. Stromal tissues, normal epithelial cells and prostate intraepithelial neoplasia (PIN) of any grade around and distant from cancer were always negative for reelin. Reelin was found in malignant prostatic epithelial glands of 50% cases Gleason score 10, 52% Gleason score 9, 56% Gleason score 8, 18% Gleason score 7, while no sample of prostate cancers with Gleason score 6 showed reelin expression (P=0,005). As reelin staining is frequently found in high Gleason score prostate cancers, we explored whether reelin expression is influenced by single Gleason patterns. While Gleason 3 pattern did not show reelin immunoreactivity, reelin expression was found in 35% Gleason 4 patterns and 45% Gleason 5 patterns (P<0.001). Our results demonstrated for the first time that reelin is expressed in prostate cancer and not in benign prostate tissue and its expression occurs in higher Gleason score and correlates significantly with increasing of single Gleason patterns. This suggests reelin may behave as a specific histological marker and may represent a useful biomarker to predict aggressive phenotypic behavior of prostatic cancer cells.     

Topoisomerase II-alpha expression increases with increasing Gleason score and with hormone insensitivity in prostate carcinoma

AIM: To investigate and compare topoisomerase II-alpha expression in benign prostatic hyperplasia (BPH), prostate cancer of varying Gleason scores and hormone-insensitive prostate cancer. METHODS: The immunohistochemical expression of topoisomerase II-alpha antibody in the above-mentioned diagnostic categories was investigated and compared. RESULTS: Increased expression of topoisomerase II-alpha was seen in the prostate cancers of Gleason scores 7 and 8-10 (p = 0.000) compared with prostate cancers of Gleason score 6 and BPH (p = 0.245). Statistically significant differences were found in the topoisomerase II-alpha gene expression between prostate cancers categorised by Gleason Score. Also, increased expression of topoisomerase II-alpha was seen in the known hormone-resistant prostate carcinomas compared with prostate cancers with no hormone treatment in the subgroup with Gleason scores 8-10, which approached statistical significance (p = 0.081). No statistically significant difference was observed in topoisomerase II-alpha expression between the groups with BPH and prostate carcinoma of Gleason score 6 (p = 0.245). CONCLUSION: Topoisomerase II-alpha expression was found to increase with the known prognostic marker Gleason score and with hormone insensitivity. Objective evidence is provided for clinical trials with drugs targeting topoisomerase II-alpha to be targeted to patients with prostate cancers of Gleason Score >6 and, in particular, prostate cancers of Gleason Scores 8-10.     

Decreased annexin I expression in prostatic adenocarcinoma and in high-grade prostatic intraepithelial neoplasia

AIMS: To analyse annexin I expression in prostatic carcinoma. Annexin I belongs to a family of structurally related calcium and phospholipid-binding proteins implicated in signal transduction, DNA replication, cell proliferation and apoptosis. The decreased expression of annexin I, II and VII proteins has been reported in different types of cancer. METHODS AND RESULTS: Using immunohistochemistry, we analysed annexin I expression in 77 cases of prostatic adenocarcinoma (Gleason score 6, N = 40; Gleason scores 7-8, N = 27; and Gleason scores 9-10, N = 10) and high-grade prostatic intraepithelial neoplasia (PIN, N = 50). Immunoreactivity of annexin I in tumour cells was evaluated as negative (< 5% of cells), focally positive (5-25% of cells) or positive (> 25% of cells). In contrast to positive staining in adjacent benign prostatic epithelium, annexin I expression was decreased (focally positive) in 76% of cases of high-grade PIN (P < 0.0001) and was decreased or absent in 81% of prostatic adenocarcinomas (P < 0.0001). Annexin I expression in all higher grade tumours (Gleason scores 7-10) was only focally positive or absent. CONCLUSIONS: Expression of annexin I inversely correlates with the increasing histological grade of prostatic adenocarcinoma. By showing a progressive loss of annexin I expression in high-grade PIN, intermediate-grade and high-grade cancer, our findings suggest that the loss of annexin I expression occurs early in prostatic tumorigenesis and becomes more prominent throughout tumour progression. The loss of expression of annexin I may serve as a useful marker of prostate cancer development and progression.     

Overexpression of Ets-1 proto-oncogene in latent and clinical prostatic carcinomas

AIMS: The high incidence of clinically diagnosed prostatic cancer is exceeded by the frequency of tumours detected at autopsy. The Ets-1 proto-oncogene is expressed by a variety of malignant and normal tissues. Therefore, in this study, expression of Ets-1 protein was investigated in 'latent' prostatic cancer detected at autopsy, compared with benign prostatic hyperplasia, normal prostatic tissues and clinical prostatic cancer. METHODS AND RESULTS: Using immunohistochemistry, we analysed Ets-1 expression in 95 prostatic specimens including 19 cases of latent prostatic carcinoma (LPC) and 55 cases of clinical prostatic carcinoma (CPC), 11 cases of benign prostatic hyperplasia (BPH) and 10 cases of normal prostate (NP). Differences in the incidence of LPC and CPC suggest different courses for the biological progression of prostatic cancer. There was a significant difference in the degree of Ets-1 expression in CPC and LPC (P < 0.05). Ets-1 was not expressed in BPH and NP, but in malignant cases (57 of 74; 77.0%) commonly demonstrated immunoreactivity in the tumour cells. In our study the expression of Ets-1 between benign and malignant, and well, moderately and poorly differentiated adenocarcinomas of prostatic cancer showed significant differences. The presence of Ets-1 mRNA was confirmed by in-situ hybridization in human prostatic tissues. CONCLUSION: Our results suggest that Ets-1 might play an important role in carcinogenesis and/or the progression of human prostatic carcinomas.     

Utility of alpha-methylacyl coenzyme A racemase (p504s antibody) as a diagnostic immunohistochemical marker for cancer.

Alpha-methylacyl-coenzyme A racemase (AMACR; P504S) is a mitochondrial and peroxisomal enzyme involved in the metabolism of branched-chain fatty acid and bile acid intermediates. Recently, AMACR has been demonstrated to be overexpressed in localized and metastatic prostate cancer and in high-grade prostatic intraepithelial neoplasia but not in normal prostatic glands, suggesting that it may be an important tumor marker. This study examines AMACR expression in a variety of human cancers to assess its viability as a tumor marker in the clinical setting. Two hundred sixty-three cancers from different sites were examined in three multitumor tissue micro arrays, which included two or three tissue cores (1.0 mm in diameter) from each neoplastic and normal tissue specimen. Cancers studied included breast (94 cases), prostate (38), lung (28), endometrium (27), colon (29), ovary (26), and melanoma (21). Normal tissues in the microarray were prostate (15), lung (6), endometrium (5), colon (4), ovary (2), and skin (3). Sections were immunostained, after prior pressure cooker antigen retrieval, using rabbit monoclonal AMACR antibody (1:40) (Zeta Corp, Sierra Madre, CA) and horseradish peroxidase-labeled polymer conjugated secondary antibody (Envision, Dako, Carpinteria, CA). A section of prostate cancer and prostatic intraepithelial neoplasia was used as positive control. Protein expression was scored as negative, weak (faint cytoplasmic or granular apical staining), moderate (diffuse granular cytoplasmic stain), and strong (diffuse intense cytoplasmic stain). Only moderate and strong staining was considered as positive staining, based on prior work. AMACR protein overexpression was found in several cancers, including prostate (34/38 [89.5%]), colon (13/29 [44.8%]), lung (4/28 [14.3%]), melanoma (2/21 [9.5%]), endometrium (2/27 [7.4%]), and breast (3/94 [3.2%]). None of the ovarian cancers (26 cases) demonstrated AMACR overexpression. AMACR expression was not present in any of the normal tissues nor in benign prostatic tissue associated with prostate carcinomas. This study suggests that AMACR is potentially an important tumor marker, particularly for prostate and colon cancer. It may be a useful adjunct to an immunohistochemical panel employed in the differential diagnosis of colon versus ovarian and breast carcinoma; the latter two infrequently express AMACR.     

Alpha-methylacyl-CoA racemase: a multi-institutional study of a new prostate cancer marker

AIM: To test whether alpha-methylacyl-CoA racemase (AMACR) is a sensitive and specific marker of prostate cancer. METHODS AND RESULTS: The expression levels of AMACR mRNA were measured by real-time polymerase chain reaction. A total of 807 prostatic specimens were further examined by immunohistochemistry specific for AMACR. Quantitative immunostaining analyses were carried out by using the ChromaVision Automated Cellular Imaging System and the Ariol SL-50 Imaging System, respectively. AMACR mRNA levels measured in prostatic adenocarcinoma were 55 times higher than those in benign prostate tissue. Of 454 cases of prostatic adenocarcinoma, 441 were positive for AMACR, while 254 of 277 cases of benign prostate were negative for AMACR. The sensitivity and specificity of AMACR immunodetection of prostatic adenocarcinomas were 97% and 92%, respectively. Both positive and negative predictive values were 95%. By automatic imaging analyses, the AMACR immunostaining intensity and percentage in prostatic adenocarcinomas were also significantly higher than those in benign prostatic tissue (105.9 versus 16.1 for intensity, 45.7% versus 0.02% and 35.03% versus 4.64% for percentage, respectively). CONCLUSIONS: We have demonstrated the promising features of AMACR as a biomarker for prostate cancer in this large series and the potential to develop automated quantitative diagnostic tests.     

Role of cytologic criteria in the histologic diagnosis of Gleason grade 1 prostatic adenocarcinoma

Gleason grade 1 prostatic adenocarcinoma is defined by its gland architecture, which resembles that of benign prostate more than any other grade. It is characterized by closely spaced glands and expansile tumor border. Cytoplasm is clear to pale, superficially identical to benign nodular hyperplasia (BPH). However, there is recent evidence that prostatic "clear-cell carcinoma," including grade 1, has cytoplasm whose composition is distinctively different from BPH, being filled with lipid rather than with the protein-rich granules that characterize benign secretory cells or the nongranular protein matrix of other prostate cancers. We reasoned that grade 1 cancer might also have additional distinctive cellular features; we tested this hypothesis by observations on 17 grade 1 carcinoma foci found as components of transition zone clear-cell cancers. Unlike BPH secretory cells, cells of grade 1 cancer were uniformly large with even, straight borders laterally and luminally. Nuclei appeared sometimes benign but were fixed in a basal row dissimilar to the uneven distribution in BPH. Nuclear pyknotic foci, blue-tinged cytoplasm, and abundant dense luminal secretion were distinctively common. Immunostain for glutathione-S transferase was negative in grade 1 cancer but lightly positive in BPH secretory cells. These cytologic findings were proposed to be useful as diagnostic clues, especially in small-needle biopsy samples, in which architecture may be difficult to interpret. HUM PATHOL 32:441-446.     

Alpha-methylacyl coenzyme A racemase immunoreactivity in partial atrophy of the prostate

It was reported that 15 of 19 consultation cases of prostatic partial atrophy were a-methylacyl coenzyme A racemase (AMACR)-positive. We investigated partial atrophy cases from a single institution using a standard AMACR immunostaining method. Immunohistochemical analysis was performed using an antibody cocktail containing p63, high-molecular-weight keratin (34bE12), and AMACR antibodies on 122 foci of partial atrophy. AMACR staining was analyzed in partial atrophy (n = 122) and compared with adjacent benign glands (n = 122) and prostatic carcinomas (n = 28). Of 122 foci of partial atrophy, 38 (31.1%) showed AMACR immunoreactivity. Typically, AMACR staining was weak or moderate. In addition, 82 (67.2%) showed patchy to negative distribution of basal cells. Partial atrophy may show AMACR immunoreactivity when using a 34bE12, p63, and AMACR antibody cocktail staining method. Compounding this problem, focal lack of basal cells may be seen. However, the AMACR staining pattern of partial atrophy is usually comparable to that of adjacent benign glands and substantially different from adenocarcinoma.     

Analysis of alpha-methylacyl-CoA racemase (P504S) expression in high-grade prostatic intraepithelial neoplasia

Alpha-methylacyl-CoA racemase (AMACR), also known as P504S, is a recently identified molecular marker for prostate cancer. The expression of AMACR/P504S has also been observed in high-grade prostatic intraepithelial neoplasia (PIN), a precursor lesion of prostate cancer. However, a detailed study focusing on the analysis of AMACR/P504S expression in high-grade PIN has not been performed. In this study, we analyzed AMACR/P504S expression by immunohistochemistry in 3954 prostatic ducts and acini with high-grade PIN from 140 prostatectomy specimens. AMACR/P504S immunoreactivity was measured as negative (0), weakly positive (+1), moderately positive (+2), and strongly positive (+3). AMACR/P504S immunoreactivity was detected in 90.0% (126/140) of high-grade PIN cases, although only 41.5% (1642/3954) of prostatic glands involved by PIN showed AMACR/P504S immunoreactivity. A significantly higher AMACR/P504S-positive rate (56.0%) was found in isolated high-grade PIN glands adjacent to cancer (distance less than 5 mm) compared with those away from cancer (distance more than 5 mm; 14%, P < 0.0001). High-grade PIN glands adjacent to cancer also showed a higher (P < 0.0004) AMACR/P504S intensity (1.62) than did those away from cancer (1.11). Our results suggest that PIN strongly positive for AMACR/P504S might be more closely associated with cancer than PIN negative or weakly positive for AMACR/P504S. This study provides additional evidence to link high-grade PIN as a precursor lesion to prostatic adenocarcinoma.