Parents who smoke may put their children at a higher risk for genetic changes associated with childhood leukemia – particularly acute lymphocytic leukemia (ALL), according to the results of a study published in Cancer Research.
Using material from the California Childhood Leukemia Study, researchers from the University of California San Francisco's Helen Diller Family Comprehensive Cancer Center analyzed pretreatment tumor samples from 559 patients with ALL to determine if the eight genes frequently deleted in ALL were absent from tumor samples. These included: CDKN2A, ETV6, IKZF1, PAX5, RB1, BTG1, PAR1 region, and EBF1. Parents' tobacco use was assessed using interview-assisted questionnaires. Researchers also used biomarkers to analyze children's exposure to maternal smoking during pregnancy.
They found that nearly two-thirds of samples were discovered to already contain at least one of these somatic deletions.
The total number of deletions per case was positively correlated with increased tobacco exposure, especially in children with mothers who had:
- ever smoked (ratio of means [RM] = 1.31; 95% CI 1.08-1.59)
- smoked during pregnancy (RM=1.48; 95% CI 1.12-1.94)
- smoked during breastfeeding (RM=2.11; 95% CI 1.48-3.02)
The magnitude of this association was greater in male children, compared with female children (p=0.04).
Limitations include a small study population, variety among samples, human error in questionnaires, and lack of knowledge as to when the deletion occurred.
Source: Reuters, April 6, 2017; Smith A, Kaur M, Gonseth S, et al. Correlates of prenatal and early-life tobacco smoke exposure and frequency of common gene deletions in childhood acute lymphoblastic leukemia.