XPA and Cowden syndrome 1: To evaluate the relationships between different XPA rs10817938 genotypes and CS in the control and smokers, we distributed the study based on smoking duration (short-term smokers ≤ five years and long-term smokers > five years), frequency of smoking (≤10 times and >10 times), gender (males and females), and the average age of smokers (≤28 years and >28 years).