In recent years there have been enormous studies made toward understanding diagnosis and treatment of cancer. Although there has been a great deal learned about cancer, the treatments available for it have not progressed nearly as much. Attempted removal of the tumor followed by chemotherapy and radiotherapy still prevail as the most effective treatments used. The present study used the electromagnetic fields (4.5 Hz) to treat tumor implanted in mice. The Polymerase Chain Reaction/Restriction Fragment Length Polymorphisms (PCR/RFLPs) technique was selected as a biomarker to evaluate the effect of exposure to electromagnetic fields in implanted Ehrlich tumor of female BALB/C mice. Eighty mice used and divided into four groups (20 each); control, radiated (control exposed to 4.5 Hz), infected (control infected by Ehrlich tumor) and infected exposed (infected exposed to 4.5 Hz). The duration of exposure was for two hours every two days. Electromagnetic field exposure includes group 2 and group 4. DNA genome was extracted and p53 suppressor gene detected (~2130 bp). AatI, BanII, EaeI restriction endonucleases did not differentiate between the PCR products (p53 genes) of the four groups (control, radiated, infected and infected exposed mice groups). BanI, DraI, DraIII, HaeII and PstI differentiated between the four groups. The results approved that the electromagnetic fields could treat the tumor and PCRRFLPs could be useful diagnostic technique.