The breast cancer movement was started because at the time, male-only cancers (such as prostate and testicular cancers) were getting far more funding and research, while breast cancer was essentially being ignored despite being at least an order of magnitude more common.
That it's more common has probably made it easier to do research on once it gained sufficient visibility and funding.
That it's more common has probably made it easier to do research on once it gained sufficient visibility and funding.