GSTM1 and anemia (phenotype): According to the stage, grade, and clinical aspects of cancer, the treatment plan will differ, and with these variations, therapy-associated complications may occur, one of which is chemotherapy-induced anemia that, based on studies outside Saudi Arabia, may arise in over 80% of patients [4], and according to World Health Organization (WHO) standards, females with hemoglobin (Hb) level below 12 g/dL and males below 13 g/dL (normal range: 13-16 g/dL in females and 14-17 g/dL in males) are considered anemic [5].