title: Prognostic significance of Bcl-xL gene expression in human colorectal cancer.
abstract: Bcl-xL is a pro-survival member of the Bcl-2 family that plays indispensable roles in regulating cell survival and apoptosis. It is overexpressed in many malignant tumors including colorectal cancer (CRC). However, it is still unclear if Bcl-xL can be used as an independent molecular marker for predicting the prognosis of CRC patients. In this study, reverse transcription-PCR assay was performed to detect the expression of Bcl-xL mRNA in CRC and corresponding non-tumor colon tissues. Immunohistochemistry was performed to detect the immunolocalization of Bcl-xL protein in sixty-eight primary CRC tissue samples. The association between Bcl-xL protein expression and clinicopathological factors of CRC patients was analyzed and the survival was assessed by the Kaplan-Meier method and proportional hazards model. The averaged level of Bcl-xL mRNA expression in CRC tissues (0.85±0.13) was significantly higher than that in non-tumor colon tissues (0.08±0.02). Immunohistochemical staining showed that the Bcl-xL protein was mainly located in the cytoplasm of tumor cells. The level of Bcl-xL protein expression was closely correlated with tumor differentiation (P=0.002), lymph node metastasis (P=0.010), venous permeation (P=0.004), and Duke's classification (P=0.021). Furthermore, patients with high Bcl-xL expression showed poorer overall survival than those with low Bcl-xL expression (P=0.016). Univariate and multivariate analysis indicated that the status of Bcl-xL protein expression might be an independent prognostic marker for CRC patients (P=0.032). Taken together, immunohistochemical assessment of status of Bcl-xL protein may offer a valuable approach for predicting survival after curative surgery for colorectal cancer.
authors.affiliation: Department of Oncology, Affiliated Nanjing First Hospital, Nanjing Medical University, Nanjing, People's Republic of China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Jin-Song
authors.forename: Wang
authors.initials: W
authors.lastname: Zhao-Xia
authors.forename: Lv
authors.initials: L
authors.lastname: Cheng-Yu
authors.forename: Liang
authors.initials: L
authors.lastname: Xiao-Di
authors.forename: Sun
authors.initials: S
authors.lastname: Ming
authors.forename: Guo
authors.initials: G
authors.lastname: Yuan-Yuan
authors.forename: De
authors.initials: D
authors.lastname: Wei
mesh_terms: D014408:Biomarkers, Tumor; D015179:Colorectal Neoplasms / Q000235:genetics / Q000401:mortality / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D016019:Survival Analysis; D051020:bcl-X Protein / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D051020:bcl-X Protein