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.     

Id-1基因与前列腺癌之关系

Id蛋白是碱性螺旋-环-螺旋(bHLH)转录因子之抑制因子。Id-1蛋白是细胞分化的负性调节因子所以有促进肿瘤发生之功能。本概述近几年我们研究室在探索Id-1基因及其功能方面的工作。从动物前列腺癌模型中首次发现Id-1蛋白之过度表达到人前列腺癌标本中得到验证，以及最后在体外培养的前列腺癌细胞株对Id-1基因之功能研究。实验表明Id-1是通过抑制P16／RB抑癌基因以及激活有丝分裂原活化蛋白激酶(MAPK)的途径而引起前列腺癌细胞增殖。结果并提示Id-1基因在前列腺癌细胞从激素依赖型转变为非激素依赖型中起着关键性的作用。     

Enhanced expression of parathyroid hormone-related protein in prostate cancer as compared with benign prostatic hyperplasia

Parathyroid hormone-related protein (PTHrP) has been shown to be the primary factor responsible for humoral hypercalcemia of malignancy. Recently PTHrP has been shown to be an early-response gene that may be involved in cellular proliferation or differentiation. In addition, PTHrP has been implicated in the pathogenesis of bone metastases. Bone metastases are a significant complication in patients with prostate cancer. We compared the expression of PTHrP by immunohistochemical staining using a monoclonal antibody directed against epitope between amino acids [53–64] in benign prostatic hyperplasia (BPH) with that in various stages of prostate cancer. Tissue sections were obtained on formalin-fixed paraffin-embedded blocks from BPH, well-differentiated prostate cancer, poorly differentiated prostate cancer, lymph node metastases (n = 15 each), and normal prostate (n = 2). In the normal prostate tissue there was no staining observed. In BPH, 13 of 15 tissue samples were positive for PTHrP immunoreactivity. An average of 33% of the cells stained positive with 1+ intensity. All samples from prostate cancer stained positive for PTHrP. In the samples from well-differentiated prostate cancer, an average of 87% of cells stained positive for PTHrP, whereas 100% of cells were positive in poorly differentiated and metastatic tumors. The intensity of staining was 3+ in well-differentiated tumors and 4+ in poorly differentiated tumors. Therefore, the expression of PTHrP is enhanced in prostate cancer as compared with BPH and is greater in poorly differentiated carcinoma as compared with the well-differentiated tumors. The role of PTHrP in the pathogenesis of prostate cancer deserves further study.     

前列腺增生组织中间质细胞增殖和表型转化与雌激素受体α表达的关系

目的 比较人正常前列腺(NP)和前列腺增生(BPH)中间质细胞标记蛋白、增殖细胞核抗原(PCNA)和雌激素受体α(ERα)的表达差异,并检测BPH组织间质细胞标记蛋白与PCNA或ERα同时呈阳性染色的细胞.方法 对4例NP和8例BPH连续切片应用免疫组织化学方法,观察波形蛋白(vimentin)、α-平滑肌肌动蛋白(α-SMA)、肌球蛋白(myosin)、PCNA和ERa的表达定位.结果 与NP相比在BPH中,α-SMA阳性染色细胞显著增加;波形蛋白在间质中阳性染色细胞有所增加,在腺泡基底层及临近腺泡外层间质中阳性染色细胞明显增加;在临近腺泡外的数层间质细胞中肌球蛋白和ERα由部分阳性变为完全阴性染色,而在远离腺泡的间质中其阳性染色细胞由散在斑块状分布变为簇状密集排列;PCNA在间质中阳性染色细胞有所增加,在基底细胞层中阳性染色细胞显著增加.连续切片免疫组织化学染色显示,在腺泡上皮基底层存在PCNA与波形蛋白、ERα共定位的细胞;在间质中存在肌球蛋白与ERα共定位的细胞.结论 与NP相比,BPH间质细胞表型发生明显变化,且其增殖和表型转化与ERα表达定位的改变密切相关.     

前列腺癌雄激素受体表达与细胞凋亡的关系

目的：探讨前列腺癌雄激素受体与细胞凋亡的关系及其生物学特性,方法：56例前列腺癌和20例良性前列腺增生症,应用免疫组化方法检测石蜡蜡包埋的组织切片中雄激素受体（AR）表达和应用原位末端标记技术（TUNEL）检测细胞凋亡指数（AI）。结果：AR在良恶性前列腺组织中的表达差异无显著性（P＞0．05）。AR和AI与前列腺癌Gleason分级无关。AI在前列腺癌组织中的表达明显高于良性前列腺增生症（P＜0．05）,AR阳性的前列腺癌AI亦明显高于AR阴性的前列腺癌。结论：前列腺癌组织中AR的表达可诱导其细胞凋亡,并对前列腺癌的功能性分类和内分泌治疗的疗效判断具有实用的临床意义。     

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.     

前列腺癌中EZH2 mRNA及蛋白表达与细胞增殖的关系

目的 探讨EZH2 mRNA和蛋白在前列腺癌中的表达及其与肿瘤细胞增殖的关系.方法 通过组织芯片技术,应用原位杂交和免疫组化方法检测48例前列腺癌中EZH2 mRNA和蛋白的表达以及Ki-67增殖指数,同时检测15例良性前列腺增生组织(BPH)和12例高级别上皮内瘤变(HGPIN)中EZH2 mRNA和蛋白的表达.结果 前列腺癌组织中EZH2蛋白和mRNA阳性率分别为87.50%和81.25%,均高于BPH和HGPIN,差异有显著性(P<0.05).EZH2蛋白与mRNA表达之间差异无统计学意义(P>0.05).EZH2蛋白的表达与Gleason分级、TNM分期相关(P<0.05),与患者年龄和术前血清前列腺特异抗原(PSA)水平无关(P>0.05).EZH2 mRNA的表达与TNM分期相关(P<0.05),与患者年龄、术前PSA水平及Gleason分级无关(P>0.05).EZH2蛋白表达程度与Ki-67细胞增殖指数呈明显正相关(r=0.746,P<0.05).结论 EZH2 mRNA及其蛋白在前列腺癌中表达上调,通过促进肿瘤细胞增殖使得肿瘤发生、发展,有望成为预测前列腺癌恶性程度进程的参考指标.     

Vascular endothelial growth factor expression in untreated and androgen-deprived patients with prostate cancer

The aim of the study was to investigate immunohistochemically the expression of vascular endothelial growth factor (VEGF) in untreated and androgen-deprived patients with prostate cancer. The study included 20 patients with prostate cancer who had undergone transurethral prostatectomy due to infravesical obstruction. All patients had been receiving androgen deprivation therapy for at least 3 months. Transurethral prostatectomy specimens were examined for VEGF expression after androgen deprivation, and the biopsy samples of the same patients were used for the evaluation of VEGF expression before androgen deprivation. VEGF expression was analyzed using immunohistochemistry. Staining patterns determined by the staining scores were compared before and after treatment. The correlation of VEGF expression with PSA, Gleason score, and the percent change in PSA after treatment was also investigated. Eligible biopsy specimens were available in 15 of the 20 patients, allowing for the evaluation of VEGF expression before treatment. All prostate cancer specimens were positive. VEGF was localized mainly in the cytoplasm or on the membrane of carcinoma cells. Staining was strong in 86.7% of patients before androgen deprivation. Heterogeneous staining (strong in 25%, moderate in 35%, and weak in 40%) was observed after treatment. Staining scores were significantly higher in patients before androgen deprivation and showed a significant decrease after androgen deprivation (p = 0.007). Tumor staining correlated with Gleason score. No significant correlation was determined between VEGF expression and pre-treatment PSA and percent change of PSA after treatment. Immunohistochemical results indicate that VEGF expression is downregulated by androgen deprivation therapy. VEGF may be a potential target for therapeutic intervention in prostate cancer.     

Histone H1 expression in human prostate cancer tissues and cell lines

Histone H1, one of the histone superfamilies, is known to determine chromatin structure and alter gene expression. It also contributes to regulation of cell proliferation in breast cancer. We hypothesized a similar association in prostate cancer, and therefore examined relationships between histone H1 expression and Gleason pattern, Ki-67 and androgen receptor levels in a series of prostate cancer tissues and cell lines. Histone H1 positive cancer cells increased with the Gleason pattern. Gleason pattern 3 tumors were divided into two groups, one with high histone H1 positivity (H1-high cases, 60-100% positivity) and the other with low histone H1 positivity (H1-low cases, 0-20% positivity). Ki-67 or androgen receptor positivity in H1-high cases was significantly higher than in H1-low cases. PC3 cells demonstrated more frequent histone H1 and Ki-67 positivity as compared to LNCaP cells. Silencing of histone H1 by siRNA transfection significantly reduced cell proliferation in LNCaP and PC3. These findings suggest that histone H1 expression is associated with the Gleason pattern, cell proliferation and androgen receptor expression in prostate cancers.     

ENDOD1在前列腺癌组织及细胞中的表达及意义

目的:观察比较核酸内切酶结构域内含蛋白1(endonuclease domain containing1,ENDOD1)在良性前列腺增生和前列腺癌组织中的表达差异;筛选存在ENDOD1特异性低表达的前列腺癌细胞系,继而通过调控该细胞ENDOD1蛋白表达,研究其在前列腺癌细胞中的生物学功能,初步探索ENDOD1基因与前列腺癌发生、进展的联系。方法:利用免疫组化SP法检测20例良性前列腺增生和21例前列腺癌术后标本组织中ENDOD1表达情况;利用RT-qPCR和Western blot方法观察ENDOD1的mRNA和蛋白在前列腺正常上皮细胞和不同类型前列腺癌细胞中的表达差异,筛选出特异性低表达细胞系;构建pCMV-N-Flag-ENDOD1重组质粒,转染前列腺癌细胞株,过表达ENDOD1蛋白,通过MTT法测定调控前后前列腺癌细胞活力的变化,流式细胞术检测细胞周期和凋亡,Transwell实验评价肿瘤细胞迁移和侵袭能力的改变。结果:免疫组化评分的方差分析结果显示ENDOD1表达与前列腺癌Gleason评分呈负性关联;RT-qPCR和Western blot实验结果表明ENDOD1在雄激素非依赖性前列腺癌细胞系PC3和DU145中存在着特异性低表达(P0.05)。同时,MTT实验显示,在DU145细胞中,过表达ENDOD1肿瘤细胞活力显著下降(P0.05);而流式细胞术检测结果表明过表达ENDOD1能够使DU145细胞周期停滞在G_0/G_1期,但细胞凋亡率无明显差异。此外,在Transwell实验中,过表达ENDOD1的DU145细胞迁移和侵袭能力明显下降(P0.05)。结论:ENDOD1在Gleason评分越高的前列腺癌中表达越低,同时在雄激素非依赖性前列腺癌细胞系存在着特异性低表达;而过表达ENDOD1能明显抑制雄激素非依赖性前列腺癌细胞的生长、迁移和侵袭能力。     

Androgen Receptor Expression and Cellular Proliferation During Transition from Androgen-Dependent to Recurrent Growth after Castration in the CWR22 Prostate Cancer Xenograft

Androgen receptor expression was analyzed in the CWR22 human prostate cancer xenograft model to better understand its role in prostate cancer recurrence after castration. In androgen-dependent tumors, 98.5% of tumor cell nuclei expressed androgen receptor with a mean optical density of 0.26 +/- 0.01. On day 2 after castration androgen deprivation decreased immunostained cells to 2% that stained weakly (mean optical density, 0.16 +/- 0.08). Cellular proliferation measured using Ki-67 revealed <1% immunostained cells on day 6. Androgen receptor immunostained cells increased to 63% on day 6 and 84% on day 32 although immunostaining remained weak. Cellular proliferation was undetectable beyond day 6 after castration until multiple foci of 5 to 20 proliferating cells became apparent on day 120. These foci expressed increased levels of prostate-specific antigen, an androgen receptor-regulated gene product. In tumors recurrent 150 days after castration androgen receptor-immunostaining intensity was similar to CWR22 tumors from intact mice although the percentage of cells immunostained was more variable. The appearance of proliferating tumor cells that expressed androgen receptor and prostate-specific antigen 120 days after castration suggests that these cells represent the origin of recurrent tumors.     

Expression of basal cell keratins in human prostate cancer metastases and cell lines.

Within normal human prostate epithelium, basal and luminal cells can be discriminated by their expression of keratins (K). While basal cells express K5/14, luminal cells show expression of K8/18 and an intermediate cell population can be identified by co-expression of K5/18. Prostate cancer is predominantly composed of luminal and neuroendocrine cells, while a minority of cells have a basal phenotype. In order to distinguish between basal and intermediate cells, and to assess the effects of androgen deprivation on prostate cancer, 56 human prostate cancer metastases and three cancer cell lines were characterized using antibodies to K5, K14, K18, and the neuroendocrine marker chromogranin A (ChA). The staining was performed on paraffin tissue and visualized by the avidin-biotin-peroxidase complex method. Protein expression was quantified as the number of positive cells in 20 high power fields (HPF; 400x). Keratin expression in the prostate cancer cell lines LNCaP, DU145, and PC3 was analysed by immunofluorescence with triple staining and confocal laser scanning microscopy. Prostate cancer metastases were consistently positive for K18 and negative for K14, irrespective of hormonal therapy. K5 expression was displayed in 28.9% of the tumours without treatment, in 75% after androgen deprivation, and in 57.1% of hormone-escaped prostate carcinomas. After androgen deprivation, the number of K5-expressing cells increased significantly. While androgen-dependent prostate cancer showed a median of 0 cells/20 HPF (range 0-50), regressed tumours displayed 22.5 (range 0-65) and hormone-escaped tumours 7.5 (range 0-361) positive cells/20 HPF. Expression of ChA was observed in 47.4% of the androgen-dependent tumours. The number of neuroendocrine cells was not significantly affected in regressed or hormone-escaped disease. The androgen-dependent cell line LNCaP stained for K18, while the androgen-independent lines DU145 and PC3 both expressed K5 and 18. Expression of K5 in the absence of K14 identifies the existence of an intermediate cell population in prostate carcinoma. Accumulation of intermediate cells in regressed and hormone-escaped prostate cancer indicates that for their survival, these cells are androgen-independent.     

Comparison of 34betaE12 and P63 in 100 consecutive prostate carcinoma diagnosed by needle biopsies.

P63, a homologue of p53, was recently identified as a useful basal cell-specific marker. We compared the sensitivity and specificity of p63 with the widely used high-molecular-weight keratin 34betaE12 for the diagnosis of prostate carcinoma in needle biopsies. We selected 100 consecutive prostate carcinoma diagnosed by needle biopsies with an adequate number of cancerous glands on the slide. We chose 1 representative hematoxylin and eosin-stained slide from each case and gave it a Gleason score. The same paraffin block was retrieved for 34betaE12 and p63 stains. We compared staining patterns of 34betaE12 and p63 on both malignant glands and benign glands and recorded basal cell density (percentage of basal cells with positive staining in the benign glands). The cases were divided into 3 groups according to the Gleason score: 5 to 6 (31 cases), 7 (46 cases), and 8 to 10 (23 cases). In 20 cases, focal and patchy staining in a basal cell distribution in malignant glands (range, 1%-20%; mean, 6.6%) was demonstrated (19 by both stains and 1 by 34betaE12 only). In 1 case with a Gleason score of 9, the cancer cells, not the basal cells, were stained focally by p63 but not by 34betaE12. Higher-grade tumors demonstrated higher numbers of malignant glands with basal cell staining (1.65% for Gleason 7, 1.26% for Gleason 8-10, compared with 0.42% for Gleason 5-6). The overall specificity of the absence of basal cell staining in the malignant glands for 34betaE12 and p63 was 98.63% and 98.60%, respectively. In 17 cases, both stains revealed total absence of basal cell staining in some benign glands (range, 1%-10%; mean, 3.5%). The overall sensitivity in identifying basal cells in benign glands was 99.48% and 99.44% for 34beta12 and p63, respectively. Basal cell density was higher for 34betaE12 in comparison with p63 (92% vs. 87%). For diagnosing prostate carcinoma in the needle biopsies, p63 is as specific and sensitive Hospital as 34betaE12 and therefore can be used as a complementary basal cell-specific stain for 34betaE12 in difficult cases.     

Hepatocellular carcinomas show abnormal expression of fibronectin protein.

Fibronectin plays an important role in cell-to-cell adhesion, cell migration, and cell signaling. In the liver, fibronectin expression has been studied primarily as a component of the extracellular matrix, but little information is available on the expression of fibronectin protein in the neoplastic cells of hepatocellular carcinomas (HCCs). Twenty-four surgically resected HCCs were immunostained with fibronectin. Tumor and normal liver tissues were concurrently analyzed in all cases, and expression in the tumor was evaluated in comparison to the nonneoplastic liver. The average age at resection was 54 +/- 18 years for the 18 men and 6 women. Twenty-one of the cases were classic HCCs including 6 cases that were well differentiated, 12 cases moderately differentiated, and 3 cases poorly differentiated. The remaining 3 cases were moderately differentiated fibrolamellar carcinomas. In the normal liver, fibronectin labeled the sinusoids and weakly to moderately stained the cytoplasm of hepatocytes. In HCCs, 15/24 showed overexpression of fibronectin in the cytoplasm, 8/24 showed no change from the nonneoplastic liver, and one case showed decreased cytoplasmic staining. In addition, an abnormal membranous staining pattern was noted in 16/24 HCCs. In contrast to the HCCs, none of the three fibrolamellar carcinomas showed increased cytoplasmic or membranous staining. Excluding fibrolamellar carcinoma, increased cytoplasmic staining and/or an abnormal membranous staining was noted in 19/21 (90%) of HCCs. Fibronectin shows abnormal cytoplasmic and/or membranous staining in the majority of HCCs. The implications of fibronectin overexpression are uncertain but may reflect a critical step in tumor genesis.     

The role of cytokeratins 20 and 7 and estrogen receptor analysis in separation of metastatic lobular carcinoma of the breast and metastatic signet ring cell carcinoma of the gastrointestinal tract

Metastatic signet ring cell carcinomas of unknown primary site can represent a clinical problem. Gastrointestinal signet ring cell carcinomas and invasive lobular carcinomas of the breast are the most common sources of these metastases. Immunohistochemical algorithms have been successfully used in the search for the unknown primary adenocarcinomas. In the present study a series of primary invasive lobular breast carcinomas (79 cases) and their metastases and a series of gastrointestinal signet ring cell carcinomas (22 primary and 13 metastases) were stained with monoclonal antibodies for cytokeratin (CK) 20 and CK7 and for estrogen receptors (ER). The staining was evaluated as negative (no staining), focally (less than 10% of the tumor cells stained) or diffusely positive. All the primary and metastatic gastrointestinal signet ring cell carcinomas proved to be CK20 positive, while only 2/79 (3%) of the primary and 1/21 metastatic lobular carcinomas (5%) stained positively for this CK. None of the gastrointestinal carcinomas and the majority of the lobular carcinomas expressed ER. The majority of the tumors were CK7+. Using CK20 alone, 33 of 34 metastases could be properly classified as gastrointestinal (CK20+) or mammary (CK20-). ER identified 31/34 of breast cancer metastases. By combining the results of CK20 and ER staining all the metastases could be properly classified as the CK20+/ER- pattern identified all the gastrointestinal tumors.