Genetic and environmental factors are both contributor of the predisposition of cancer (10). Knowing the nature of these contributers is important to prevent the diseases ( adapting lifetstyle and behavior to the conditions). Sometimes genetic factors and cancer that are associated with each other affect significantly clinical intervention. For instance, as mentioned before if mutations occur at breast cancer susceptibility gene 1 and 2 (BRCA1,BRCA2) and at the same time if mutations occur at tumor suppressor genes , there is higher risk to develop the breast, ovarian, hematologic and prostate cancers(11). For these reason, regular screening, surgical measures and receive adjuvant therapies would undergo to prevent. Also genetic tests are used to analyse the inherited mutations DNA mismatch repair genes. Risk of advencing of colon cancer is high at the MLH1 and MSH2 genes(12). Under the light of this information cancer can be precluded with early screening colonoscopy to early detect and treat for cancer. Cancer databases that are about mutation types and polymorphisms are updated for public. These resources can be used to identify new biomarkers for screening.(13) Tumor classification and subtyping Personalized medicine changes the traditional classification of cancers from histologic scale to the molecular scale. Although histological scale does’nt give more information about prognosis , personalized tretment alternatives and risk of recurrence, molecular scale offers to give a detailed information about diseases processes(14). DNA, RNA, miRNA and protein have been used for molecy-ular analyses to classfy different tumor types into the subtypes. Each of them have an unique prognostic outcome that can not be identified with the traditional morphologic ways(15). Generally molecular scale for classification is used for acute myeloid leukemia, glioblastoma, breast cancer , and renal cell carcinoma , and to differentiate between Burkitt’s lymphoma and diffuse B-cell lymphoma. This classification that offers prognosis and treatment options can help to the patients about management of disease.(16) Targeted therapy and predictive markers for treatment efficiency The basic aim of the personalized medicine is applying right therapy to the right population of people by defining disease at the moecular level. So, identifying differences among the individuals support the new treatment methods and pharmaceutical companies to develop new cancer drugs. Patients who have similar clinical outcome and histological tumor type can give different response to the same drug(17). Prediction of who will be a nonresponders reduces the harmfull effect of drug on nonresponders like a potential toxic effect of drug and cost effect. Also when drug companies develop new drug, they focu>