In agreement with our findings in the pancreas, when the LKB1 gene sequence was determined in primary lung adenocarcinomas, only 8 of 27 tumors (of 80 cancers total) that had a mutation or deletion of LKB1 exhibited biallelic loss,32 suggesting that a monoallelic mutation in LKB1 is sufficient to drive cancer progression. This evidence concerns the gene STK11 and lung adenocarcinoma.