INTRODUCTION: STUDIES HAVE SHOWN THAT CANCER IS AMULTI FACTORIAL DISEASE THAT IN ITS PATHOGENESIS, IN ADDITION TO GENETIC DISORDERS, THE EFFECT OF ENVIRONMENTAL FACTORS CAN ALSO BE POINTED. AMONG ALL ENVIRONMENTAL FACTORS, TOBACCO THAT CONSIDERED AS THE LEADING CAUSE OF RESPIRATORY AND CARDIOVASCULAR DISEASE PLAYS A KEY ROLE IN CANCER PATHOGENESIS AND PROGRESSION. MORE THAN 5, 000 CHEMICALS AND 62 CARCINOGENES HAVE BEEN DETECTED IN TOBACCO, WHICH COULD CONTRIBUTE TO TUMORGENESIS THROUGH ACTIVATING ONCOGENES, INHIBITION OF TUMOR SUPPRESSOR GENES, GENETIC AND EPIGENETIC CHANGES, ALTERATION OF GROWTH PATHWAYS, ANGIOGENESIS AND METASTASIS...