A 68-year-old man presents with a 3-month history of bloody diarrhea and weight loss. Colonoscopy reveals a 4-cm mass in the sigmoid colon; biopsy confirms adenocarcinoma. A tumor cell line derived from this specimen divides indefinitely in culture without entering replicative senescence, despite normal p53 function. The cells maintain telomere length through continuous proliferation. There is no evidence of apoptosis. Which of the following molecular changes most directly explains this capability?
- A)Inhibition of cyclin D
- B)Increased mismatch repair fidelity
- C)Loss of angiogenic potential
- D)Telomerase activation allowing limitless replicationGABARITO
- E)Enhanced apoptosis through caspase activation
Explicação
Many malignant cells reactivate telomerase, which maintains telomere length and prevents replicative senescence. This contributes to one of the hallmarks of cancer: limitless replicative potential. Ver explicação completa e trilha adaptativa →