Novel gene hBiot2 is an independent prognostic factor in colorectal cancer patients

The present study investigated the expression of the novel gene hBiot2 in colorectal cancer (CRC) and its relationships with clinicopathological variables in CRC patients. The expression of hBiot2 in 163 primary CRCs together with the corresponding normal mucosa, 36 liver metastases and 5 colon cancer cell lines was examined using real-time PCR. In situ hybridization (ISH) was performed to evaluate the localization of hBiot2 expression in CRC and normal mucosa. hBiot2 expression at the RNA level was localized in the nucleus of tumor cells and normal epithelial cells. The mean expression of hBiot2 in the CRCs (243.571±564.569) was higher compared to the normal mucosa (107.252±413.635, P<0.0001) and liver metastasis samples (42.002±40.809, P=0.0002). hBiot2 expression was increased from stages I+II to III (P=0.047), and no difference in the expression was found in stages III and IV (P=0.452). A high value of hBiot2 was associated with a poorer prognosis compared with a low value independently of gender, age, tumor site, stage and differentiation (P=0.007, RR 7.519, 95% CI 1.729-32.704). Liver metastasis, smaller tumors, non-local recurrence and primary liver surgery alone were associated with a higher value of hBiot2 compared to larger tumors, local recurrence and repeated liver surgery (P=0.003, 0.044 and 0.026, respectively). An inverse relationship was found between hBiot2 expression and the metastatic potential of the colon cancer cell lines. Thus, increased expression of hBiot2 may be an early and interim event in the development of CRC. A higher expression of hBiot2 in primary CRC patients independently indicates a poorer prognosis.