Quiz: Understand the Genetics of Skin Cancer

Question 1

Answer

A.2

Healthy melanocytes rarely divide, typically less than two times a year. However, upon malignant transformation into skin cancer, the proliferative index climbs as tumor cells accumulate genomic aberrations

Question 2

Answer

B.C→T, G→T

Skin cancers have higher mutational loads than many other cancer types and the number of point mutations and gene copy number alterations climbs as cancer progresses. Skin cancers tend to carry a higher number of “ultraviolet-signature” mutations, as well, such as C?T mutations caused by ultraviolet B and G→T mutations caused by ultraviolet A solar radiation.

Question 3

Answer

D.BRAF V600

Transformation frequently begins with activating BRAF V600 mutations but progression requires additional mutations, including TERT promoter mutations and ARID1A mutations affecting cell-cycle control.

Question 4

Answer

C.TP53

Progression of metastatic skin cancer is associated with mutations in the tumor suppressor protein gene TP53 and the phosphatase-and-tensin homologue PTEN gene.

Question 5

Answer

C.50%

Half of skin cancers harbor BRAF mutations, while another 25% harbor RAS mutations and 15% have NF1 mutations. BRAF mutation status is a key factor in decision making about treatment regimens including BRAF inhibitors like vemurafenib.