EGFR CNGs were significantly more frequent in never smokers, Asian ethnicity, were mutually exclusive with KRAS mutations and occurred more frequently with EGFR mutations than in wild type cases as previously described [26].
EGFR mutations in lung cancer are more frequent in never smokers and are exclusive with KRAS mutations [7], [8], [9], [10], [11].
Mutations involving the HER2 gene have been shown to be more frequent in never smokers with adenocarcinoma [9].
This is consistent with a previous study in which lung AC were more frequent in never smokers than in ever smokers in eastern Asians[ 41].
The distribution of methylation status in the three genes studied according to several personal and clinical characteristics is presented in Table 3. Methylation of CDKN2A was significantly more frequent in never drinkers, and in less severe stages at diagnosis.
Some recent studies had shown that mutations in the epidermal growth factor receptor gene, which often took place among the patients with lung AC, were more frequent in never smokers and women in eastern populations, whereas such mutations were more frequent in smokers and men in western populations [ 40, 41].
EML4-ALK translocation is more frequent in Chinese never-smokers than in Chinese smokers, which is consistent with the result in patients worldwide [ 6].
Moreover, clearance of HPV infection was more frequent in women who never smoked than in women who ever smoked, but the association was not statistically significant (data not shown).
A reviewer noted that "Laughter more frequent or more hearty was never heard in any theatre than that which more than once brought the action... to a temporary standstill".
Yet, suicide attempts were more frequent among those who had never been hospitalized in a psychiatry ward in the past (69.1%, n = 192 vs previously hospitalized 30.9%, n = 86; p = 0.01) and those who were not under the care of a psychiatrist (56.6%, n = 158 vs under psychiatric treatment 43.4%, n = 121; p = 0.004).
Moreover, PIK3CA amplification was significantly associated with smoking history and histologic type, which was more frequent in smokers compared to never-smokers, and in SCC compared to in ADC.
