KDM6A and cancer: Pharmacologic repression of the polycomb pathway by inhibition of polycomb methylase EZH2 with GSK-126 confers cisplatin resistance to TGCT cells but not other cancer cell types, while polycomb induction by inhibition of polycomb demethylases KDM6A and KDM6B with GSK-J4 sensitizes TGCT cells to cisplatin