Whole Genome Comparison of Allelic Imbalance between Noninvasive and Invasive Small-Sized Lung Adenocarcinomas

Seventy-two small-sized (≤2 cm in diameter) lung adenocarcinomas consisting of 15 noninvasive and 57 invasive tumors were subjected to whole genome allelic imbalance (AI) scanning and mutational analysis of the EGFR, KRAS , and TP53 genes to elucidate genetic pathways of early-stage lung adenocarcinomas. The chromosome 13q13 region showed the most frequent AI (58%) and was affected at similar frequencies between noninvasive and invasive tumors (53% and 60%, respectively), as EGFR and KRAS mutations were. The number of AI regions as well as the frequency of TP53 mutations in invasive tumors was significantly higher than those in noninvasive ones [9.8 ± 5.6 versus 4.8 ± 2.8 ( P = 0.00002) and 61% versus 13% ( P = 0.001), respectively]. In particular, AIs at the chromosome 11p11-p12, 17p12-p13, and 18p11 regions in invasive tumors were significantly more frequent than those in noninvasive ones ( P IA) and associated with worse prognoses ( P = 0.04) and, thus, would be involved in invasion and/or metastasis of adenocarcinoma cells and useful for the prediction of prognosis of patients with small-sized lung adenocarcinoma. [Cancer Res 2009;69(4):1615–23]