There is a genetic predisposition for some kinds of cancers, not necessarily so for many others, AND it has less than NOTHING at all to do with "inbreeding"!
From 2018 and, appropriately, the UK...
Genetic diversity, inbreeding and cancer
...and show that low genetic diversity and inbreeding associate with an increased risk of cancer in both humans and animals...
I've also been wondering if vaxx injuries run in families.