My mom had breast cancer, my grand father had collon cancer, my grandmother had lung cancer i had leukemia when should i start testing for the others?

Genetic counseling: Hi tiffany, sorry to hear ab what you/your family went through. You need to see a genetic counselor. Most large cancer centers have one. They will do a blood test or a mouth swab to check for cancer genes. Li fraumeni syndrome (and others) need to be ruled-out. When you start testing depends on the age your relatives were when diagnosed/what gene (if any) you have. Please stop smoking. Good luck!