Analysis of the molecular and clinicopathologic features of surgically resected lung adenocarcinoma in patients under 40 years old.

Abstract

The youthful lung cancer may constitute an entity with distinct clinicopathologic characteristics and a controversial prognosis compared with the older counterpart. Whether the youthful lung cancer has the exclusively distinct molecular features has not been well investigated. Thirty-six resected lung adenocarcinomas from young patients under 40 years old were analyzed concurrently for mutations in EGFR, KRAS, HER2, BRAF, AKT1, ALK, RET, TP53 and LKB1 and enrolled as the younger group. Their molecular and clinicopathologic characteristics were compared with those of 87 adenocarcinoma cases from patients above 40 years old which were collected as the older group. The comparable overall survival (OS) (P=0.942), more early adenocarcinomas (P=0.033), more wedge resections (P<0.001) and fewer smokers (P=0.004) were seen in the younger group, when compared with the clinicopathologic characteristics in the older group. Nineteen EGFR mutations (52.8%), 3 KRAS mutations (8.3%), 2 EML4-ALK fusions (5.6%) and 1 KIF5b-RET fusion (2.8%) were identified in the younger group. The difference of oncogenic mutations between the two groups was statistically insignificant (P=0.396). Twenty-six TP53 mutations (72.2%) and 4 LKB1 mutations (11.1%) were found in the younger group. When compared with the old patients, young patients showed a higher prevalence of TP53 mutations (P<0.001) and a comparable prevalence of LKB1 mutations (P=0.951). The youthful lung cancer unequivocally presented the distinct clinicopathologic characteristics including more early adenocarcinomas and fewer smokers. It showed the similar oncogenic characteristics and higher prevalence of TP53 mutations compared with the older counterpart.