Disclosed herein are methods of detecting or making risk evaluation of a cancer that has a mutated PREX2 expressed thereon. The cancer may be a primary cancer, a metastatic cancer or a recurrent cancer. According to the embodiment of the present disclosure, the mutation is G258V, S1113R, E1346D or K400fs. Also disclosed herein are methods of treating the subject in need thereof.本發明所揭露的是檢測癌症或進行癌症風險評估的方法,其中該癌症具有突變的PREX2表現。該癌症可為原發性癌症、轉移性癌症或復發性癌症。根據本發明的實施例,突變為G258V、S1113R、E1346D或K400fs。本發明也揭露治療所需個體的方法。