ETS-1 is the founding member of the ETS family of transcription factors. ETS factors have important roles in oncogenesis, signal transduction and development. In human tumors, ETS-1 is expressed in endothelial cells and fibroblasts of the tumor stroma and is proposed to play a role in tumor vascularization and invasion by upregulating expression of matrix-degrading proteases. In human carcinomas, ETS-1 is also expressed by neoplastic cells, but little is known about the functional implications of this observation. The present study aimed to detect the tumor by using electromagnetic fields through ETS-1 oncogene. The detection of point mutations correlated with diseases is currently performed by digestion of PCR products (PCR/RFLP) by using restriction endonucleases. It has been described here a method based modified on primers during the PCR, and using some restriction endonucleases (AatI, BanI, BanII, DraI, DraIII, EaeI, PstI and SacII) which create a restriction fragment length polymorphism (RFLP) indicative of the studied mutation. The present study used the electromagnetic fields (4.5 Hz); 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 were used and divided into four groups (20 each); normal, exposed (exposed to 4.5 Hz), infected (normal infected by Ehrlich tumor) and infected exposed (infected exposed to 4.5 Hz). DNA genome was extracted and ETS-1 oncogene detected (~4460 bp). AatI, BanII and EaeI restriction endonucleases did not differentiate between the PCR products (ETS-1 genes) of the four groups (normal, exposed, infected and infected exposed mice groups). DraIII, SacII, PstI, BanI and DraI differentiated between the four groups. The results proved that the electromagnetic fields could treat the tumor and PCRRFLPs were able to be a useful diagnostic technique.