The BCL11A-XL expression predicts relapse in squamous cell carcinoma and large cell carcinoma

Background: The B cell leukemia 11A ( BCL11A ) gene was identified as a proto-oncogene in hematopoietic cell malignancies and breast cancer. Alternative RNA splicing generates three main transcripts designated as Extra-long (XL; 5.9 kb/125 kD), Long (L; 3.8 kb/100 kD) and Short (S; 2.4 kb/35 kD). Our previous study results demonstrated that BCL11A expression levels were specifically upregulated in non-small cell lung cancer (NSCLC) tissues, especially in squamous cell carcinoma (SCC) and large cell carcinoma (LCC). Methods: In this study, we detected the BCL11A protein isoforms with immunohistochemistry (IHC) method in NSCLC with in a cohort (n=40) of BCL11A overexpression NSCLC patients. All 40 cases were BCL11A overexpression including 27 SCCs, 8 LCCs and 5 adenocarcinomas (ACs). Relationship between BCL11A isoforms and the clinicopathological parameters were also analyzed. Results: Compare to the BCL11A-L and S isoforms, the BCL11A-XL isoform was specifically expressed in SCC and LCC (P=0.006). There were 19 (19/40, 47.5%) cases positive for BCL11A-XL expression, SCC accounted for 63.2% (12/19) and LCC accounted for 36.8% (7/19). The survival analysis indicated that BCL11A-XL expression was an independent prognostic factor for disease-free survival (DFS) [hazards ratio (HR) 0.246; 95% confidence interval (CI), 0.065-0.939, P=0.040] but not for overall survival (OS) in patients with SCC and LCC. Conclusions: Our results demonstrated that the BCL11A-XL isoform might be a potential prognostic biomarker of SCC and LCC.