A family friend's grandmother in Ireland died of ovarian and/or uterine cancer in her late 70's, and I believe it was diagnosed in her late 60's to early 70's. The mother, who lived in the US, of this friend got breast cancer in her mid to late 50's, had a double mastectomy out of precaution (Only one breast had the cancer.), then died in her early 70's when the cancer recurred elsewhere. Now, about this friend, who lived in the US: She, herself, was diagnosed with lung cancer (though, she never smoked) when she was 50. She passed away less than 6 months after diagnosis. (Her father lived to be in his mid-80's. Curiously enough, she passed away about three months after her father died of 'old age'.) Perhaps this friend's lung cancer was not the primary one, but a metastasis from possible breast cancer, but I do not have the details on that.
The cancers in this family could have been hereditary. Also, there is a clear age progression from older age (the grandmother) to younger age (the friend herself).
Another unrelated case regarding a known genetic cancer: The mother died in her mid-40's of a rare form of cancer in her back. She had three children: two girls and one boy. One of the girls died of the same cancer when she was in her early 20's! Both had lived in the US.
Are these examples of 'genetics syndrome' that results in regression of age of onset of cancer?
I always wondered why, in the above cases I mentioned, the newer generation got the cancers at a younger age.