PINK1 Expression Is Associated with Poor Prognosis in Lung Adenocarcinoma

PTEN-induced putative kinase protein 1 (PINK1) is a serine/threonine-protein kinase that phosphorylates mitochondrial proteins and is involved in mitophagy. Thus, PINK1 may protect cancer cells against mitochondrial dysfunction during cellular stress. However, the role of PINK1 in lung cancer was rarely explored. In this study, we immunohistochemically analyzed the expression of PINK1 in 256 patients with non-small-cell lung cancer, consisting of 137 patients with adenocarcinoma (AC) and 119 patients with squamous cell carcinoma (SCC). In particular, we focused on the difference in diagnostic or prognostic value of PINK1 expression between AC patients and SCC patients. The patients with AC or SCC were divided into high or low PINK1 expression group, according to the immunohistochemical score that was based on the percentage of PINK1 positive cells and staining intensity. Among the 137 AC specimens, 52 specimens (37.96%) were judged as high PINK1 expression, and likewise, among 119 SCC specimens, 42 specimens (35.29%) were judged as high PINK1 expression. Importantly, high PINK1 expression was significantly associated with postoperative chemoresistance of AC, but not in case of SCC. Moreover, high PINK1 expression was identified as a poor prognostic factor for AC, but not for SCC. These results may reflect the biological difference between AC and SCC. In conclusion, high PINK1 expression is correlated with poor response to chemotherapy and is an independent prognostic factor for AC, but not for SCC. Our findings suggest that PINK1 detection could help stratify patients who may have poor response to chemotherapy and guide the individual treatment.