[gww]

It is common for human cancers to be polyploid after accumulate whole genome doublings (WGD), where a tumour cells goes from being approximately diploid to tetraploid. Different tumour types have higher rates of WGD, for example, glioblastoma, ovarian cancer, and pancreatic adenocarcinoma. But what usually happens is that the tumour loses parts of the doubled genome to reach a ploidy (average copy number across the genome) of 3-4ish.