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Malcolm C Pike

Publications and source records attributed to Malcolm C Pike.

42 records · Page 3Linked to original sources
PubMed2002

Galactose-1-phosphate uridyl transferase (GALT) genotype and phenotype, galactose consumption, and the risk of borderline and invasive ovarian cancer (United States).

OBJECTIVE: Previous studies have suggested that high levels of galactose consumption and/or low levels of galactose-I-phosphate uridyl transferase (GALT) activity may result in an increased risk of epithelial ovarian cancer. Similarly, some have reported that carriers of the N314D (asparagine at codon 314 replaced by aspartate) GALT polymorphism, which can be associated with low GALT activity, may have a higher risk of ovarian cancer. We examined these issues as part of a large case-control study of ovarian cancer conducted in Los Angeles between 1992 and 1998. METHODS: A total of 1,439 histologically confirmed borderline and invasive ovarian cancer cases among English-speaking non-Asian women were ascertained through the population-based cancer registry for Los Angeles County and completed in-person interviews were obtained from 689 of these (78% of cases approached). Controls consisted of 645 English-speaking non-Asian women with at least one intact ovary matched to cases on race/ethnicity (African-American, Latina, non-Latina White), date of birth (+/-3 years), and neighborhood of residence. Interviewer-administered questionnaires included information on reproductive factors, exogenous hormone use, medical history, and diet. Dietary information for the year before each case's diagnosis (and the same period for her matched control) was obtained using a self-administered food-frequency questionnaire. Blood samples were obtained from 452 controls, 136 cases with borderline ovarian cancer, and 312 cases with invasive ovarian cancer. The N314D polymorphism was characterized using PCR-RFLP and GALT enzyme activity, and was determined for a sample of the subjects with GALT genotype using an erythrocyte-based radioactive enzyme assay. RESULTS: We found no effect of N314D GALT genotype on the risk of borderline ovarian cancer (odds ratio (OR)=0.91; 95% confidence interval (CI)=0.54-1.6) or invasive ovarian cancer (OR=0.78; 95% CI= 0.53-1.2). Neither did we observe a relationship between GALT activity or lactose/galactose intake and risk of borderline or invasive ovarian cancer. Among N314D carriers, galactose consumption was associated with an increased risk of borderline (OR = 2.7, p = 0.01), but not invasive (OR = 1.2, p = 0.34), ovarian cancer; however, this result was based on only 24 N314D-positive borderline cases. CONCLUSIONS: Differences in galactose intake and GALT metabolism do not contribute significantly to the risk of ovarian cancer. There is some evidence that galactose intake may play a role in the development of borderline ovarian cancer among women who carry the uncommon GALT N314D polymorphism. More data are needed if this latter suggestion is to be definitively addressed.

Adult↗
PubMed2002

Urinary 2-hydroxyestrone/16alpha-hydroxyestrone ratio and family history of breast cancer in premenopausal women.

It has been hypothesized that the ratio of urinary 2-hydroxyestrone to 16alpha-hydroxyestrone (2-OHE1/16alpha-OHE1 represents a biomarker for breast cancer risk; the lower the ratio the higher the risk. We obtained early morning urine samples from 70 'high risk' premenopausal women who had a first degree family history of breast cancer and 27 'low risk' women with no such history. Five estrogen metabolites in urine were determined: 2-OHE1, 16alpha-OHE1, estrone (E1), estradiol (E2), and estriol (E3) conjugates. We compared geometric mean levels of each metabolite adjusted for age and weight. 'High risk' women did not have elevated levels of any of these metabolites. Instead, we observed decrements of 3-27% in women with a family history of breast cancer compared with women without such history, this difference was statistically significant for E2, 2- OHE1, and 16alpha-OHE1. The ratio of 2-OHE1/16alpha-OHE1 was identical in women with and without a family history of breast cancer. These results were unchanged, when additionally adjusted for recent intake of alcohol or cruciferous vegetables. Our data suggest that among premenopausal women, family history is not associated with higher urinary estrogen levels or a lower ratio of urinary 2-OHE1/16alpha-OHE1.

Adult↗
PubMed2002

Adolescent and adult soy intake and risk of breast cancer in Asian-Americans.

The association between soyfood intake and breast cancer risk is controversial. Most of the epidemiologic studies published on this topic in the 1990s were not designed to specifically address this question. We conducted a population-based, case-control study of breast cancer among Chinese, Japanese and Filipino women in Los Angeles County to further investigate the role of soy. Our primary objective was to quantify breast cancer risks associated with intake of soy during adolescence and adult life among Asian-American women. During 1995-1998, we successfully interviewed 501 breast cancer patients and 594 control subjects. Intake of soy among Asian-Americans is still relatively high; the median intake was 12 mg isoflavones/day, approximately one-third of that reported in a recent study in Shanghai, China. The risk of breast cancer was significantly inversely associated with soy intake during adolescence and adult life. After adjusting for age, specific Asian ethnicity, education, migration history and menstrual and reproductive factors, women who reported soy intake at least once per week during adolescence showed a statistically significantly reduced risk of breast cancer. There was also a significant trend of decreasing risk with increasing soy intake during adult life. When we considered soy intake during both adolescence and adult life, subjects who were high-soy consumers during both time periods showed the lowest risk (OR=0.53, 95% CI=0.36-0.78) compared with those who were low consumers during both time periods. Risk of breast cancer was intermediate among subjects who were high-soy consumers during adolescence and low-soy consumers during adult life (OR=0.77, 95% CI=0.51-1.10). Based on a relatively small number of subjects, the risk did not appear to differ between those who were low consumers during adolescence and high consumers during adult life. Results remained similar after adjustment for other potential confounders including other dietary and non-dietary risk factors for breast cancer. These results show that high soy intake in childhood in Asian-Americans is associated with reduced breast cancer risk. Risk may be further reduced by intake as an adult.

Asian↗
PubMed2002

Breast cancer in a multiethnic cohort in Hawaii and Los Angeles: risk factor-adjusted incidence in Japanese equals and in Hawaiians exceeds that in whites.

Few data exist on the extent to which the differences in breast cancer risk between "racial-ethnic" groups in the United States (US) are "explained" by differences in their distribution of risk factors. We have determined this for African-American (AA), native Hawaiian (NH), Japanese-American (JA), Latina-US-born (L-US), Latina-non-US-born (L-NUS), and white (W) women using prospective incidence data on 88,712 postmenopausal women recruited in 1993-1996. We identified 1,757 incident breast cancer cases through 1999 among these women (1,116 cases after excluding women with a simple hysterectomy or missing risk factor data). Data were available on seven "known" risk factors: ages at menarche and first birth; parity; age at and type of menopause; weight; hormone replacement therapy use; and alcohol consumption. The relative risks (RRs) of breast cancer (with the RR in Ws set to 1.0) for the groups were as follows: W = 1.0; AA = 0.78; NH = 1.33; JA = 0.99; L-US = 0.77; and L-NUS = 0.60. After adjustment for the risk factors, the RRs were as follows: W = 1.0; AA = 0.98; NH = 1.65; JA = 1.11; L-US = 0.95; and L-NUSB = 0.84. The slightly greater risk of the JAs compared with the Ws is in sharp contrast to the very low breast cancer rates that were observed in "traditional" Japanese women and in early Japanese migrants. The adjusted RR of NHs is 65% greater than that of Ws, and that of migrant Latinas is 16% lower than that of Ws. Elucidating the causes of the high rates in NHs is now a major focus of our efforts.

Aged↗
PubMedDate not supplied

Effect of reproductive hormones on ovarian epithelial tumors: I. Effect on cell cycle activity.

We examined the effects of the 4 major female reproductive hormones, estradiol (E2), progesterone (P4), follicle stimulating hormone (FSH), and luteinizing hormone (LH) on thymidine incorporation in benign and malignant ovarian epithelial tumors cultured in vitro. Treatment of these tumors with E2, FSH and LH resulted in increased thymidine incorporation while treatment with P4 inhibited growth as well as thymidine incorporation. The inhibitory effect of progesterone could not be reproduced by treating the cells with ligands for other steroid hormone receptors known to interact with P4 such as the mineralocorticoid and glucocorticoid receptors. All cells lines expressed at least the PR-A isoform of the progesterone receptor. ORG2058, R5020, RU486, and ZK98299 acted as progesterone receptor agonists with regard to their effect on thymidine incorporation. P4 down-regulated cyclin Bl expression and cdkl activity and up-regulated the p21 and p27 proteins. Expression of a reporter gene downstream to an AP-1 responsive element in a plasmid construct transfected into ovarian epithelial tumor cells was induced by P4 and inhibited by RU486. We conclude that P4 inhibits cell cycle activity in ovarian epithelial tumors, in part via down-regulation of the cdkl/cyclin B complex. This inhibitory effect may have therapeutic utility against ovarian epithelial tumors.

Cell Cycle↗