The trouble with looking for cancer-associated variants is that it can be difficult to tease out spurious effects (e.g. ethnicity) from causative variants. If you're interested in what genes are implicated in most types of cancer, the annotations for the NanoString panels are quite good:
The "Support documents" section of those pages has a link to an Excel file with gene lists and probe sequences. While these lists don't give information about variants that disrupt function, I'm struggling a bit to think through why it would be useful in advance to know that, unless the aim is to induce cancer through CRISPR or something like that.