MYBL2 (B-MYB) in cervical cancer: putative biomarker

Cervical cancer is the second most common cancer affecting women worldwide. It is characterized by chromosomal aberrations and alteration in the expression levels of many cell cycle regulatory proteins. MYBL2 is a member of the MYB proto-oncogene family that encodes DNA binding proteins. These proteins are involved in cell proliferation and control of cellular differentiation.

Four established cervical cancer cell lines were examined and compared with normal cervix using gene expression profiling and comparative genomic hybridization, and results were correlated to identify potential novel cervical cancer biomarkers. Results were validated using TaqMan polymerase chain reaction, and the potential role of MYBL2 as a clinical biomarker was then evaluated by immunohistochemistry on 30 tissue samples.

MYBL2 was found to be overexpressed in the cervical cancer cell lines by gene expression profiling, and this result was confirmed using TaqMan polymerase chain reaction. Analysis of comparative genomic hybridization data indicated that chromosome 20q13.1, which encodes the MYBL2 gene, was amplified in the human papillomavirus (HPV) type 16-positive CaSki and SiHa cell lines but not in the HPV-18-positive HeLa or HPV-negative C33A cell lines.

Although MYBL2 staining was predominantly absent in normal cervical epithelium, strong staining (score of 2 or 3) was identified in all cases of cervical intraepithelial neoplasia, cervical glandular intraepithelial neoplasia, and invasive cancer on immunohistochemistry. In addition, strong staining of a population of diffusely scattered single cells is identified. We postulate that these may represent so-called cancer stem-like cells.