- A Cancer cells are sometimes thought to be untargetable specifically, since every tumour cell type is assumed to rely equally on the same broad, non-specific growth signaling pathways found in common with normal healthy tissue as generally observed in typical laboratory settings under usual circumstances
- B Cancer cells become dependent on (addicted to) the activity of a specific oncogene for survival; if that oncogene is inhibited, the cell dies even though normal cells can survive without it; exploited by targeted therapies (imatinib for BCR-ABL in CML; trastuzumab for HER2+ breast cancer)
- C Oncogene addiction is sometimes thought to mean cancer is incurable, when in fact identifying a tumour's specific oncogene dependency is precisely what makes targeted, druggable therapy a realistic treatment option according to most researchers in the majority of cases studied as widely reported
- D Targeted therapies are sometimes thought to work for all cancers with complete success and no risk of relapse, despite resistant subclones routinely emerging and limiting the durability of responses in standard practice under most conditions encountered in routine practice
Correct answer: B. Cancer cells become dependent on (addicted to) the activity of a specific oncogene for survival; if that oncogene is inhibited, the cell dies even though normal cells can survive without it; exploited by targeted therapies (imatinib for BCR-ABL in CML; trastuzumab for HER2+ breast cancer)
Explanation: Oncogene addiction: despite having multiple mutations, cancer cells become 'addicted' to signaling from a dominant oncogene. Inhibiting it causes apoptosis or senescence even though normal cells can survive without it. Examples: imatinib (Gleevec) - BCR-ABL kinase inhibitor for CML (>90% remission); vemurafenib - BRAF V600E inhibitor for melanoma; erlotinib - EGFR inhibitor for lung cancer; trastuzumab (Herceptin) - anti-HER2 for breast cancer.
Concept context
Pathogens, infectious diseases, non-infectious diseases, drugs, cancer, and public health. High NEET importance.