The Prognostic Role of STEAP1 Expression Determined via Immunohistochemistry Staining in Predicting Prognosis of Primary Colorectal Cancer: A Survival Analysis

Abstract

STEAP1 (six transmembrane epithelial antigen of the prostate 1) is a transmembrane protein that functions as a potential channel or transporter protein. It is overexpressed in certain cancers and is viewed as a promising therapeutic target. However, the prognostic role of STEAP1 is still controversial, and no role for STEAP1 has yet been indicated in colorectal cancer. The aim of this study was to investigate the possible association of STEAP1 expression with colorectal cancer prognosis. STEAP1 expression was analyzed by immunohistochemical staining of a tissue array of 165 cancer specimens from primary colorectal cancer patients. The mean and medium follow-up times after surgery were 5.1 and 3.9 years, respectively. A total of 139 patients died during the 13 years of follow-up in the survey period. The prognostic value of STEAP1 with respect to overall survival was analyzed by Kaplan-Meier analysis and Cox proportional hazard models. In total, 164 samples displayed detectable STEAP1 expression in the cytoplasm and membrane. Low STEAP1 expression was correlated with poor overall survival (five-year survival: 33.7% vs. 57.0%, low expression vs. high expression, p = 0.020). Accordingly, multivariate analysis identified low STEAP1 expression as an independent risk factor (hazard ratio = 1.500, p = 0.018), especially in elderly patients or those with late stage cancers, late T values, and early N values. We suggest that analysis of STEAP1 expression by immunohistochemical staining could serve as an independent prognostic marker for colorectal patients. This finding should be validated by other investigative groups.

The Tumor Suppressive Roles and Prognostic Values of STEAP Family Members in Breast Cancer

“…It was proved that the expression of STEAP1 in prostate cancer is significantly increased, and silencing STEAP1 expression can inhibit the proliferation of prostate cancer cells and promote apoptosis [10]. Furthermore, the upregulation of STEAP1 has been also detected in lung, gastric, colorectal, renal, and bladder cancer [28][29][30][31]. Maia et al demonstrated that STEAP1 is overexpressed in human breast cancer cases [32].…”

Six-Transmembrane Epithelial Antigen of Prostate 3 Predicts Poor Prognosis and Promotes Glioblastoma Growth and Invasion

“…Recently, dysregulation of the STEAP family (STEAP1, STEAP2, STEAP3, and STEAP4) has been observed in various cancers. STEAP1 is highly expressed in many human malignancies, including prostate, lung, bladder, colon, ovarian, and Ewing's sarcoma cancers [13] , [14] , [15] . Furthermore, STEAP1 has also been identified as an intriguing target for antibody therapy in multiple solid human tumors [15] .…”

A Research of STEAP1 on the Biological Behavior of Gastric Cancer

“…The expression of STEAP1 was closely related to the malignant phenotype of cancer cells. [13,[16][17][18][19][20] However, in Lee's study, they found no correlation between expression of STEAP1 and the clinicopathological factors [21]. These con icting results indicated that the roles of STEAP1 were varied depending on different cancer types.…”