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PSCA

prostate stem cell antigen;PSCA;prostate stem cell antigen

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8q24.2

protein-coding

OBJECTIVE: To study the expression of prostate stem cell antigen (PSCA) at protein and mRNA levels in invasive micropapillary carcinoma of the breast (IMPC) and to analyze the relationship between PSCA expression and clinicopathologic features. METHODS: The expression of PSCA protein was analyzed by immunohistochemistry (LSAB) in 66 cases of IMPC and 67 cases of invasive ductal carcinoma, not otherwise specified (IDC-NOS). The association between PSCA expression and clinicopathologic features was also analyzed in IMPC. Furthermore, RT-PCR was used to detect PSCA mRNA in 10 cases of primary IMPC and 10 cases of primary IDC-NOS with paired normal breast tissues, each from the same subject. RESULTS: Immunohistochemical analysis revealed the overexpression of PSCA in 47 of 66 (71.2%) cases of IMPC and 35 of 67 (52.2%) IDC-NOS. Statistical analysis showed a significant difference of PSCA expression between IMPC and IDC-NOS (P = 0.024). In IMPC, the expression of PSCA was correlated with lymph nodes metastasis (P = 0.039). RT-PCR showed the mRNA level of PSCA was significantly higher in primary IMPC and IDC-NOS tissue than that in paired normal breast tissue (7/10 and 5/10, respectively), and it was also significantly higher in primary IMPC tissue than that in IDC-NOS tissue. CONCLUSION: PSCA might play an important role in lymph node metastasis in IMPC.

PSCA and Oct-4 have been thought as markers of cancer stem cells. Although overexpression of PSCA and Oct-4 in cancer has been reported, little is known about the clinical and pathological significance with PSCA and Oct-4 expression in gallbladder adenocarcinoma. In this study, overexpression of PSCA and Oct-4 was detected in gallbladder adenocarcinoma (54.6% and 55.6%). Less expression of PSCA and Oct-4 was detected in the pericancerous tissues (19.6% and 21.7%), gallbladder polyps (13.3% and 13.3%), and gallbladder epithelium with chronic cholecystitis (14.3% and 14.3%). The overexpression of PSCA and Oct-4 was significantly associated with differentiation, tumor mass, lymph node metastasis, invasion of gallbladder adenocarcinoma, and decreased overall survival. Our study suggested that overexpression of PSCA and Oct-4 might be closely related to the carcinogenesis, progression, metastasis, or invasive potential and prognosis of gallbladder carcinoma.

PURPOSE: Prostate stem cell antigen (PSCA) is expressed by a majority of prostate cancers and is a promising therapeutic target. PSCA protein and mRNA expression was examined in prostate cancer bone, lymph node, and visceral metastases to assess the potential of PSCA as an immunotherapeutic target in advanced prostate cancer. EXPERIMENTAL DESIGN: Immunohistochemical analysis of PSCA protein expression and quantitative mRNA expression analysis of PSCA was done on clinical specimens of prostate cancer bone, lymph node, and visceral metastases. PSCA protein and mRNA expression levels were quantified and compared between available matched pairs of bone and lymph node or visceral metastases. RESULTS: Bone metastases stained with higher intensity of PSCA compared with lymph node or liver metastases in seven of eight (87.5%) matched pairs (P = 0.035). PSCA mRNA expression was equal or greater than that of LAPC-9, a PSCA expressing xenograft, in 12 of 24 (50%) cases of prostate cancer metastases and was significantly correlated with PSCA protein expression (sigma = 0.84, P = 0.0019). Overall, PSCA protein expression was detected in 41 of 47 (87.2%), four of six (66.7%), and two of three (66.7%) cases of bone, lymph node, and liver metastases, respectively. Mean PSCA staining intensity was significantly higher in prostate cancer bone metastases compared with lymph node metastases (2.0 +/- 0.02 versus 0.83 +/- 0.31, P = 0.014). CONCLUSIONS: Prostate cancer metastases express PSCA. However, greater PSCA staining intensity and level of PSCA mRNA expression was associated with bone metastases compared with lymph node metastases. This study suggests that PSCA is a promising tumor marker and potential therapeutic target for patients with metastatic prostate cancer.

The development of novel clinical tools to combat cancer is an intense field of research and recent efforts have been directed at the identification of proteins that may provide diagnostic, prognostic and/or therapeutic applications due to their restricted expression. To date, a number of protein candidates have emerged as potential clinical tools in the treatment of prostate cancer. Discovered over ten year ago, prostate stem cell antigen (PSCA) is a cell surface antigen that belongs to the Ly-6/Thy-1 family of glycosylphosphatidylinositol-anchored proteins. PSCA is highly overexpressed in human prostate cancer, with limited expression in normal tissues, making it an ideal target for both diagnosis and therapy. Several studies have now clearly correlated the expression of PSCA with relevant clinical benchmarks, such as Gleason score and metastasis, while others have demonstrated the efficacy of PSCA targeting in treatment through various modalities. The purpose of this review is to present the current body of knowledge about PSCA and its potential role in the treatment of human prostate cancer.