Aims: ASCL2, a basic helix-loop-helix (bHLH) transcription factor, is putatively involved in tumour progression. This study aimed to evaluate ASCL2 expression level in non-small-cell carcinoma (NSCLC) and assess its prognostic value for patients.
Methods: ASCL2 protein expression was detected by immunohistochemistry (IHC cohort) in 79 cases of squamous cell carcinoma (SCC) and 67 cases of adenocarcinoma (AC). Kaplan-Meier analysis and Cox regression analysis were performed to evaluate the prognostic significance of ASCL2. The same analyses were conducted in a cohort (n=790) from The Cancer Genome Atlas database (TCGA) to validate the expression pattern and prognostic value of ASCL2.
Results: ASCL2 expression levels were significantly increased in SCC compared with normal lung tissue (p<0.001) and AC (p=0.008). High ASCL2 expression was associated with advanced tumour-node-metastasis (TNM) stage (p=0.023) and worse differentiation status (p=0.001) in SCC, but a positive correlation between ASCL2 expression level and advanced TNM stage (p=0.016) was observed in AC. Kaplan-Meier analysis showed that ASCL2 was prognostic in SCC (p=0.004) but not in AC (p=0.183). Multivariable Cox regression analysis indicated that elevated expression of ASCL2 was an independent prognostic factor (HR 2.764; p=0.030) in SCC patients. The expression pattern and prognostic significance of ASCL2 in SCC and AC were validated using the TCGA cohort.
Conclusions: Elevated expression of ASCL2 may identify an aggressive subgroup in SCC and serve as an independent prognostic indicator in these patients.
Keywords: CANCER RESEARCH; HISTOPATHOLOGY; LUNG CANCER.
Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/