Surgery

Advances in the understanding of cancer at the molecular biology level have added prognostic information and possible therapeutic alternatives. The expression or absence of various oncogenes independently predict prognosis in various tumor types. Protein expression of the c-erb B2 oncogene is associated with a favorable therapeutic response and improved survival in esophageal adenocarcinoma.¹ In breast cancer, the coexpression of several oncogenes (c-fos, c-myc, Ha-ras) endowed tumors with a more aggressive phenotype, leading to increased occurrence of invasive carcinoma and local recurrence while adversely affecting disease-free and overall survival.² Multiple genetic mutations have been identified in the stepwise progression of the development of colorectal carcinoma. The loss of heterozygosity on chromosome 17p strongly correlates with lymphatic and/or vascular microinvasion and, therefore, is a negative prognostic indicator independent of cancer stage.³

The precise determination of the molecular events involved in the neoplastic transformation process may lead