HNF4A and neoplasm: To determine whether these tumors are indeed a mix of LUSC and LUAD cells, or perhaps biphenotypic (with both LUSC and LUAD markers expressed in the same populations of cells), we used our transcriptional profiling to compare dual expression of LUSC and LUAD markers by identifying p63+CK5+ tumor cells and evaluating them for hepatocyte nuclear factor 4 alpha (Hnf4a) expression.