Tumors extracted from mice injected with 786-O cells co-expressing Type 2a pVHL mutant (Y98H or Y112H) and a stabilized form of HIF2α (proline hydroxylation site double mutant, P405A and P531A) were observed to have increased RCC tumor mass as compared to mice injected with cells lacking the stabilized HIF2α. Here, EPAS1 is linked to neoplasm.