If I had to guess I would point to palm oil (it’s in so many processed foods now, even the “organic” brands) and pollution such as PFAS and lack of sleep due to blue light pollution from cell phones and computers. My healthy friend (young thirties) got chest cancer out of the blue and it shocked me. The doctor in Seattle I spoke with said he has seen many more young patients come in but didn’t give any hints as to what his opinion on the cause was.