Prognostic value of p16 protein in patients with surgically treated non-small cell lung cancer; Relationship with Ki-67 and PD-L1

Background/Aim: Non-small cell lung cancer (NSCLC) is the leading cause of cancer death. Patients eligible for surgery have better overall survival rate than patients who are not eligible. We investigated the prognostic value of p16 in patients who underwent surgery for lung cancer, in association with other factors such as PD-L1 and Ki-67. Materials and Methods: Expression of p16 was evaluated along with the presence of Ki-67 and PD-L1 in 256 NSCLC patients treated only surgically. Results: Adenocarcinoma was the prevalent histotype (56%) followed by squamous cell (29%) and differentiation grade of 3 was the most common (60%). p16 was detected in 83 patients (30%): Low positivity (<10% cells) was observed in 30 samples (11%) and high positivity (>10 % cells) in 53 patients (20%). Ki-67 was detected in 89 patients (34%) with mild positivity in 46 patients (10-25% cells), moderate positivity (26-75% cells) in 30 patients (11%), and high positivity (>75% cells) in 13 patients (5%). An influence of p16 expression (p<0.05) along with grading and staging on overall survival (OS) was found. The average OS was 36 months, but the OS increased up to 54 months when patients were stratified according to p16 expression levels. The stratification by staging showed a significant prognostic value for p16 at an early stage (p<0.014). Conclusion: P16 significantly influences prognosis, notably at an early stage, along with other variables such as grading and staging.