We also found that BRD4 levels were different among NSCLC patients between squamous cell carcinomas and adenocarcinomas, between lymph node metastasis and lymph node non-metastasis, between TNM stages I–II and TNM stages III–IV and between low differentiation and high differentiation, we performed a subgroup analysis classified by these clinicopathological features. Here, BRD4 is linked to squamous cell carcinoma.