Question

Cancer can result from a variety of different mutational events. Which of the following is LEAST likely to result in the initiation of a cancerous tumor?AA receptor mutation results in activation of a cell-division pathway in the absence of the appropriate ligand.BA mutation results in the loss of the ability to produce a tumor-suppressor protein.CA defect in a cell-cycle checkpoint prevents a cell from entering the S phase.DAt the anaphase checkpoint, separation of chromatids occurs without all centromeres being attached to kinetochore microtubules from both poles.

Answer 1

C. A defect in a cell-cycle checkpoint prevents a cell from entering the S phase.

D is incorrect since defects in proteins such as MAD2 that function predominantly at the SAC (spindle checkpoint or anaphase checkpoint,) also are characterized in multiple myeloma (cancer). So this is a probable cause of cancer.