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While many studies have investigated the overall nutritional status of children with cancer, the status with regard to vitamin B6 has not been investigated. Vitamin B6 is an important factor in over 100 different chemical reactions within cells. It has been hypothesized by some that abnormalities in vitamin B6 metabolism could play a role in the development of cancer. For this reason, the vitamin B6 status was investigated in 37 children with leukemia and in 37 age-matched controls. The study examined the plasma levels of pyridoxal 5'-phosphate (PLP), which is the biologically active form of the vitamin; it is generally believed that the circulating plasma levels of this vitamin are a fair indication of the total body store. It was found that the patients generally had significantly lower levels of PLP than the control subjects, although not all the leukemia patients were below the normal range. However, a low level of a vitamin in a cancer patient does not mean that a low level contributed to the development of the disease. While some experiments in animals have indicated that vitamin B6 deprivation can contribute to the development of cancer, there is no reason to think that the children studied in the present research were deprived prior to the development of their disease. Testing of the siblings of these patients did not reveal any abnormalities, and it seems likely that the depressed levels of vitamin B6 observed in these patients are a result of inadequate nutrition resulting from cancer, rather than a contributing cause. However, it cannot be ruled out that at least some of the observed reduction in circulating vitamin B6 may result from the increased use of the vitamin by the leukemic cells themselves. Therefore, the possibility that any supplementation of the diets of these children with vitamin B6 may actually provide the cancer cells with more of what they need to grow must be considered. More must be learned about the metabolism of vitamin B6 in leukemic children before guidelines for vitamin supplementation are developed. (Consumer Summary produced by Reliance Medical Information, Inc.)

To evaluate the role of in utero exposure to metronidazole (a carcinogen in some animal models) and the risk of subsequent cancer, the authors conducted a retrospective cohort study of childhood cancer. The cohort included 328,846 children younger than 5 years born to women enrolled in Tennessee Medicaid at any time between the last menstrual period (LMP) and the date of delivery. The cohort was identified by linking files of Tennessee Medicaid mothers ages 15-44 years and children and the children's birth and death certificates for the period January 1, 1975 through December 31, 1992. Exposure data were obtained from Medicaid pharmacy records and exposure was defined as filling a metronidazole prescription that had at least a day's supply between the 30 days prior to the LMP and the date of delivery. Study cases were cohort children diagnosed with a first primary cancer before age 5 years, identified by linking the cohort with a statewide childhood cancer database for the study period. Cohort members contributed 1,172,696 person-years of follow-up for analysis, with children exposed (8.1%) and not exposed (91.9%) in utero to metronidazole contributing 79,716 and 1,092,980 person-years, respectively. Of 952 children younger than 5 years in the statewide cancer database, 175 met study eligibility criteria. Of these, 42 had leukemia, 30 had central nervous system (CNS) tumors, 28 had neuroblastoma, and 75 had other cancers. Using Poisson regression modeling, children exposed to metronidazole in utero had no significant increase in adjusted relative risk (RR) for all cancers (RR: 0.81; 95% confidence interval [95% CI], 0.41-1.59), leukemia (no exposed case), CNS tumors (RR: 1.23; 95% CI, 0.29-5.21), neuroblastomas (RR: 2.60; 95% CI, 0.89-7.59), and other cancers (RR: 0.57; 95% CI, 0.18-1.82). The authors conclude that although there was no increase in risk for all cancers associated with in utero exposure to metronidazole, the observed increased risk for neuroblastomas, although not significant, requires further evaluation. Cancer 1998;83:1461-1468. © 1998 American Cancer Society.