Question at position 16 Exposure to UV radiation causes approximately 90% of all skin cancer cases.TrueFalse单项选择题
A
True
B
False

Question

Question at position 16 Exposure to UV radiation causes approximately 90% of all skin cancer cases.TrueFalse

BlackTom AI · Accepted Answer

Ultraviolet (UV) radiation damages DNA in skin cells by creating specific lesions (cyclobutane pyrimidine dimers and 6-4 photoproducts) that, if unrepaired, lead to mutations driving skin cancer development.

1. Relevant knowledge points and concepts
- Types of UV: UVA (longer wavelength, penetrates deeper), UVB (shorter, more DNA-damaging), UVC (filtered by atmosphere).
- DNA damage and mutation: UVB and UVA produce DNA lesions that can cause mutations in oncogenes and tumor suppressor genes (e.g., p53).
- Epidemiology: Sun exposure and artificial sources (tanning beds) are the dominant environmental risk factors for the three major skin cancers (basal cell carcinoma, squamous cell carcinoma, melanoma).
- Preventive data: Public health sources estimate about 80–90% (commonly cited ~90%) of non-melanoma skin cancers and a large proportion of melanomas are attributable to UV exposure.

2. Step-by-step reasoning
- Step 1: Identify mechanism — UV causes DNA photoproducts leading to permanent mutations if unrepaired.
- Step 2: Relate mechanism to disease — Accumulation of mutations in skin cells increases risk of skin cancers (basal cell, squamous cell, melanoma).
- Step 3: Use epidemiologic evidence — Case-control and population-attributable-risk studies link lifetime UV exposure and tanning bed use to the majority of skin cancer cases.
- Step 4: Synthesize — Given the biologic plausibility and strong epidemiologic association, the statement that exposure to UV radiation causes approximately 90% of all skin cancer cases is supported.

3. Calculations
- No numerical calculation required; the ~90% figure is an epidemiologic estimate based on population-attributable risk from studies and public health reports.

4. Why the correct answer is correct
- Because both mechanistic (DNA damage) and large-scale epidemiologic data repeatedly show UV exposure is the predominant cause of skin cancers, supporting the ~90% attribution.

5. Why the other option is incorrect
- Choosing False would ignore the extensive evidence linking UV exposure to the vast majority of skin cancers and the widely cited statistic that about 80–90% are UV-attributable.

6. Conclusion
- Therefore, the correct answer is True, which matches the provided answer.

Question at position 16 Exposure to UV radiation causes approximately 90% of all skin cancer cases.TrueFalse单项选择题

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