Cytogenetic studies in a 40-year-old woman with follicular lymphoma demonstrate a t14;18 chromosomal translocation involving the bcl-2 gene. Constitutive expression of the protein encoded by the bcl-2 gene inhibits which of the following processes in this patient's transformed lymphocytes?: (A) Apoptosis, (B) DNA excision repair, (C) G1-to-S cell cycle progression, (D) Oxidative phosphorylation
Answer is A. Many human cancers show abnormalities in the control of apoptosis. For example, follicular B-cell lymphomas display a characteristic chromosomal translocation in which the bcl-2 gene is brought under the transcriptional control of the immunoglobulin light-chain gene promoter, thereby causing overexpression of bcl-2. As a result of the antiapoptotic properties of bcl-2, the neoplastic clone accumulates in lymph nodes. Since its demonstration in follicular lymphomas, bcl-2 expression has been observed in a variety of other human cancers. None of the other choices describes the function of bcl-2.Diagnosis: Follicular lymphoma