Highlights of This Issue

Abstract

Observational studies on polyunsaturated fatty acids (PUFAs) and overall cancer outcomes have yielded mixed findings, and more importantly, are limited by their ability to infer causality. In this study, Liyanage, Ong, and colleagues evaluated whether there is genetic evidence to support causal claims for the relationship between several PUFAs and cancer outcomes through a series of mendelian randomization analyses using data from the UK Biobank cohort. Among all the PUFAs tested, most presented limited evidence for an effect on the risk of being diagnosed/dying from cancer except ALA, where increased genetically predicted ALA was associated with a reduction in risk. For individual common cancers, higher LA concentrations were shown to be protective for colorectal cancer risk.Wiemels and colleagues demonstrated using high quality population registry data evidence that early clinically-diagnosed CMV infection (during pregnancy for the mother or within the neonate) is a strong risk factor for childhood hematologic malignancies. This provocative observation suggests that prevention of vertical CMV transmission during pregnancy would be an effective approach at leukemia prevention. While additional research is needed on the mechanisms, the results support a scenario where the timing of infection of this ubiquitous virus; that is, before an infant can mount an adaptive immune response, may be critical in the etiology of leukemia.Increased intratumoral synthesis of cholesterol has been described in primary prostate cancers from patients who ultimately develop metastases. Khan, Stopsack, and colleagues studied the vitamin D-regulated enzyme sterol-27-hydroxylase (CYP27A1), which lowers intracellular cholesterol by converting it to 27-hydroxycholesterol. Among participants of the Health Professionals Follow-up Study and the Physicians’ Health Study with prostate cancer, low CYP27A1 mRNA was associated with higher cholesterol synthesis and with higher risk of metastases and prostate cancer death. There were no strong associations with markers of vitamin D signaling. These findings further support the hypothesis that cholesterol accumulation is a feature of lethal prostate cancer.Numerous systemic treatments, including targeted therapies, have been developed for advanced-stage non-small cell lung cancer but many patients remain untreated. Maguire and colleagues used California Cancer Registry data to examine the role that health insurance plays in the receipt of systemic treatments. Only half (51%) of patients received such treatment and those with Medicaid were significantly less likely to receive it compared with their privately insured counterparts. Source of health insurance influences care received. Further research is warranted to better understand the barriers to treatment that patients with Medicaid face.