An atlas of gene programs in non-small cell lung cancer delineates novel patterns of lineage vacillation, plasticity, and aggressiveness

Combinations of molecular programs can be altered in cancer cells and contribute to tumor initiation and aggressiveness. We developed a novel framework called a Gene Program Association Study (GPAS) to create an atlas of gene co-expression modules in cancer cells from 127 primary non-small-cell-lung cancers (NSCLCs) and determine their association with clinical and histopathological features. Lung adenocarcinoma (LUAD) displayed "lineage vacillation" defined by extensive heterogeneity of modules from different alveolar cell types. Modules associated with late-stage LUAD were found in cells from early-stage tumors suggesting that aggressive phenotypes can be observed before clinical progression. Basal- and squamous-like intermediate cells were observed in the transition to invasive mucinous LUAD. In lung squamous cell carcinoma, a novel subtype was identified with lower levels of canonical squamous modules and higher levels of fibrinogen. Overall, this atlas elucidated the combinations of molecular programs in cancer cells that contribute to heterogeneity and aggressiveness in NSCLC. Statement of SignificanceWe performed a Gene Program Association Study (GPAS) to create an atlas of gene modules in cancer cells from NSCLCs. This atlas revealed extensive lineage vacillation, combinations of modules that defined late-stage disease, novel routes of lineage plasticity, and novel subtypes in lung adenocarcinoma or lung squamous cell carcinoma.