48. Following statements are made about some of the abnormally expressing proteins in human cancers:
    (1) Increased telomerase expression always contributes to increased cell death in cancer cells.
    (2) Overproduction of anti-apoptotic protein (Bcl2) can lead to inappropriate cell survival and is associate with chronic lymphoblastic leukemia (CLL).
    (3) The E5, E6 and E7 proteins encoded by human papilloma virus (HPV) are tumor suppressors.
    (4) Overexpression of cyclin D1 or loss of p16 and Rb can cause inappropriate, unregulated passage through the restriction point in late G1.
    Which of the following options represents the combination of all correct statements?
    (1) A and B (2) A and C
    (3) B and D (4) C and D

The correct combination of all correct statements about abnormally expressing proteins in human cancers is:

(3) B and D

Explanation

• Statement (1) is incorrect because increased telomerase expression does not lead to increased cell death; rather, it contributes to increased cell survival and cellular immortality by maintaining telomere length, which allows cancer cells to continue dividing.​

• Statement (2) is correct: Overproduction of the anti-apoptotic protein Bcl-2 prevents apoptosis and is associated with chronic lymphocytic leukemia (CLL), leading to inappropriate cell survival.​

• Statement (3) is incorrect: The E5, E6, and E7 proteins of human papillomavirus (HPV) are not tumor suppressors but rather oncoproteins that inactivate tumor suppressors like p53 and Rb, promoting oncogenesis.​

• Statement (4) is correct: Overexpression of cyclin D1 or loss of p16 and Rb disrupts cell cycle checkpoints, leading to unregulated progression through the G1 restriction point and uncontrolled proliferation [general oncogenic mechanisms].