Genetic testing of cheek or blood cells reflects inherited susceptibility rather than changes occurring in specific tissues over a lifetime.

“why is it that you don't need to look directly at breast cells why is it that we can infer that what we see in a cheek cell an endothelial cell or an epithelial cell rather in the cheek or in a monocyte in the blood is also captured in in mammary tissue good question and the answer is it's probably not um so what you're doing when you're doing the cheek sample the blood sample is you're really getting at The Germ line so you're mostly getting it what you were born with what that inherited susceptibility is”