This cohort consists of 470 lung adenocarcinoma (LUAD) and 482 breast carcinoma (BRCA) tumours, containing 152 triple negative breast carcinomas (TNBC), 266 HER2-negative (HER2-), 22 HER2-positive (HER2+) and 42 other breast carcinomas (“Methods” section). Here, ERBB2 is linked to lung adenocarcinoma.