My sister says she has endometrial cancer. are family members more likely to get the same thing?

Possible: But not likely. Most patients with endometrial cancer have risk factors that have to do with estrogen exposure (like early menarche, late menopause). Only a small percentage are genetic.

Endometrial cancer: Endometrial cancer can be hereditary but is more commonly linked to obesity. Families more at risk usually also have a history of breast cancer, ovarian cancer (brca 1 or 2), or colon cancer (hnpcc/lynch syndrome).