Thyroid hormone receptor α1 acts as a new squamous cell lung cancer diagnostic marker and poor prognosis predictor.

Lung cancer is considered the major cause of cancer-related deaths worldwide. Unfortunately, all chemotherapy regimens used in lung cancer treatment showed nearly the same efficacy. Finding a new therapeutic target that can be used as an alternative after the failure of or in association with chemotherapy to improve the prognosis is an urgent demand. Up to date, it is Known that thyroid hormones (THs) and Thyroid hormone receptors (THRs) control the progression of several types of tumours. Nevertheless, their role in non-small cell lung cancer (NSCLC) is unknown. This study investigated the expression of THRα1 in NSCLC cases and its correlation to tumour clinicopathological parameters to shed new light on the relevance of THRα1 in lung cancer. Immunohistochemistry utilizing THRα1 antibody was performed on tissue sections obtained from 80 patients diagnosed with NSCLC. We also investigated the expression of THRα gene in Microarrays of lung squamous cell carcinoma (SCC) and adenocarcinoma (AC) patients by using GEO data sets on https://www.ncbi.nlm.nih.gov . We showed, for the first time, the expression of THRα1 in NSCLC. Intermediate and high THRα1 expressions were detected in (25% and 66.7%) of SCC cases respectively. High THRα1 expression was associated with shorter OS. On the other hand, 86.7% of AC cases revealed low THRα1 expression. Inflammatory cells in SCC cases showed high THRα1 expression. By analysing GEO data sets, a significant increase in THRα gene expression was found in SCC compared to AC cases. Our study underscores the possibility of using THRα1 expression not only as a prognostic marker, but also as an innovative diagnostic additive tool for lung SCC, which could be tested as a potential therapeutic target for SCC in the future.