Lynne R. Wilkens

Intake of Flavonoids and Lung Cancer

Background: To investigate the possible relationship between intake of flavonoids-powerful dietary antioxidants that may also inhibit P450 enzymes-and lung cancer risk, we conducted a population-based, case-control study in Hawaii. Methods: An in-person interview assessed smoking history and usual intake of 242 food items for 582 patients with incident lung cancer and 582 age-, sex-, and ethnicity-matched control subjects. Subjects who donated a blood sample were genotyped for the P450 enzyme variant allele CYP1A1 * 2 by use of a polymerase chain reaction-based method. Logistic regression analysis was used to compute odds ratios (ORs) and 95% confidence intervals (CIs). All P values are two-sided. Results: After adjusting for smoking and intakes of saturated fat and β-carotene, we found statistically significant inverse associations between lung cancer risk and the main food sources of the flavonoids quercetin (onions and apples) and naringin (white grapefruit). The lung cancer OR for the highest compared with the lowest quartile of intake was 0.5 (95% CI = 0.3-0.9) for onions (P for trend =.001) and 0.6 (95% CI = 0.4-1.0) for apples (P for trend =.03). The OR for the highest compared with the lowest tertile of intake for white grapefruit was 0.5 (95% CI = 0.2-0.9) (P for trend =.02). No association was found for important food sources of other flavonoids. Using published food-composition data for flavonoids, we found an inverse association between intake of quercetin and risk of lung cancer (P for trend =.07) that appears consistent with associations for its food sources. The effect of onions was particularly strong against squamous cell carcinoma (a cell type specifically associated with CYP1A1 * 2 in our study) and was modified by the CYP1A1 genotype, suggesting that CYP1A1 may play a role in this association. Conclusion: If replicated, particularly in prospective studies, these findings would suggest that foods rich in certain flavonoids may protect against certain forms of lung cancer and that decreased bioactivation of carcinogens by inhibition of CYP1A1 should be explored as underlying mechanisms.

Animal fat consumption and prostate cancer: a prospective study in Hawaii.

Whereas case-control studies have been very consistent in suggesting a positive association between intake of dietary fat, especially animal fat, and prostate cancer, the results from past cohort studies have been mostly inconclusive. In this study, we evaluated consumption of high-fat animal products, raw vegetables, and fresh fruits, as well as obesity, smoking, and drinking, in relation to subsequent occurrence of prostate cancer. We studied a cohort of 20,316 men of various ethnicities interviewed between 1975 and 1980 in Hawaii. As of December 1989, 198 incident cases with invasive prostate cancer were identified by computer-assisted linkage of this cohort to the statewide Surveillance, Epidemiology, and End Results registry. Relative risks (RRs) for prostate cancer computed by proportional hazards regression were elevated for intake of beef [RR for highest to lowest tertile of intake = 1.6; 95% confidence interval (CI) = 1.1–2.4] and milk (RR = 1.4; 95% CI = 1.0–2.1), and for a summary variable for intake of high-fat animal products (RR = 1.6; 95% CI = 1.0–2.4). Weight was not consistently associated with prostate cancer, but there was an association with height (>167 cm) (RR = 1.8; 95% CI = 1.0–3.2 for the third and fourth quartiles relative to the lowest quartile in height). These associations were stronger in men diagnosed before age 72.5 years. The risk estimates for raw vegetable and fresh fruit intakes were close to 1.0. Smoking and alcohol drinking appeared to be unrelated to risk. This study provides further evidence for a role of animal fat in the etiology of prostate cancer and indicates that it may act by shortening the latency period of the disease.

Lung cancer occurrence in never-smokers: an analysis of 13 cohorts and 22 cancer registry studies.

Background Better information on lung cancer occurrence in lifelong nonsmokers is needed to understand gender and racial disparities and to examine how factors other than active smoking influence risk in different time periods and geographic regions. Methods and Findings We pooled information on lung cancer incidence and/or death rates among self-reported never-smokers from 13 large cohort studies, representing over 630,000 and 1.8 million persons for incidence and mortality, respectively. We also abstracted population-based data for women from 22 cancer registries and ten countries in time periods and geographic regions where few women smoked. Our main findings were: (1) Men had higher death rates from lung cancer than women in all age and racial groups studied; (2) male and female incidence rates were similar when standardized across all ages 40+ y, albeit with some variation by age; (3) African Americans and Asians living in Korea and Japan (but not in the US) had higher death rates from lung cancer than individuals of European descent; (4) no temporal trends were seen when comparing incidence and death rates among US women age 40–69 y during the 1930s to contemporary populations where few women smoke, or in temporal comparisons of never-smokers in two large American Cancer Society cohorts from 1959 to 2004; and (5) lung cancer incidence rates were higher and more variable among women in East Asia than in other geographic areas with low female smoking. Conclusions These comprehensive analyses support claims that the death rate from lung cancer among never-smokers is higher in men than in women, and in African Americans and Asians residing in Asia than in individuals of European descent, but contradict assertions that risk is increasing or that women have a higher incidence rate than men. Further research is needed on the high and variable lung cancer rates among women in Pacific Rim countries.

A genome-wide association study identifies a new ovarian cancer susceptibility locus on 9p22.2

Epithelial ovarian cancer has a major heritable component, but the known susceptibility genes explain less than half the excess familial risk. We performed a genome-wide association study (GWAS) to identify common ovarian cancer susceptibility alleles. We evaluated 507,094 SNPs genotyped in 1,817 cases and 2,353 controls from the UK and ∼2 million imputed SNPs. We genotyped the 22,790 top ranked SNPs in 4,274 cases and 4,809 controls of European ancestry from Europe, USA and Australia. We identified 12 SNPs at 9p22 associated with disease risk (P < 10−8). The most significant SNP (rs3814113; P = 2.5 × 10−17) was genotyped in a further 2,670 ovarian cancer cases and 4,668 controls, confirming its association (combined data odds ratio (OR) = 0.82, 95% confidence interval (CI) 0.79–0.86, Ptrend = 5.1 × 10−19). The association differs by histological subtype, being strongest for serous ovarian cancers (OR 0.77, 95% CI 0.73–0.81, Ptrend = 4.1 × 10−21).

Evidence of an X-linked or recessive genetic component to prostate cancer risk

We used data from a population-based cohort study of blacks, Hispanics, Japanese and whites to examine the frequency of prevalent prostate and breast cancer by family history status of first-degree relatives (parents and siblings). Independent of race, the age-adjusted relative risk for prevalent prostate cancer in subjects with affected brothers was approximately two times that in subjects with affected fathers (P < 0.00005). No such excess risk for breast cancer was observed among subjects with affected sisters compared to those with affected mothers (age- and race-adjusted relative risk = 1.10, P= 0.34). The magnitude of the relative risk for prostate cancer in sibling-versus parent-affected groups was significantly different from that of the comparable relative risk for breast cancer (P < 0.00005). An excess risk of prostate cancer in men with affected brothers compared to those with affected fathers is consistent with the hypothesis of an X-linked, or recessive, model of inheritance.

An epidemiologic study of thyroid cancer in Hawaii

A population-based case-control interview study was designed to test the hypothesis that dietary iodine or the consumption of goitrogenic vegetables increases the risk of thyroid cancer. A total of 191 histologically confirmed cases (64 percent female) and 441 matched controls from five ethnic groups in Hawaii were available for analysis. Among women, intake of seafood (especially shellfish), harm ha (a fermented fish sauce), and dietary iodine were associated with an increased risk of cancer, whereas consumption of goitrogenic (primarily cruciferous) vegetables was associated with a decreased risk. Non-dietary risk factors included miscarriage (especially at first pregnancy), use of fertility drugs, family history of thyroid disease, obesity, and work as a farm laborer. The odds ratio for the combined effect of a high iodine intake and a first-pregnancy miscarriage was 4.8 (95 percent confidence interval [CI]=1.2 – 19.2); and for high iodine intake and use of fertility drugs 7.3 (95 percent CI=1.5 – 34.5). Among men, positive associations were found for obesity, work as a farm laborer, and a past history of benign thyroid disease. Although this study identified several dietary and non-dietary risk factors for thyroid cancer, it could not fully explain the exceptionally high incidence rates among Filipino women in Hawaii.

B-vitamin intake, metabolic genes, and colorectal cancer risk (United States)

Objective: This population-based case–control study was designed to investigate the interrelationships between polymorphisms in the methylenetetrahydrofolate (MTHFR C677T and A1298C) gene and other genes (MTR A2756G; MTRR A66G and CBS 844ins68), intake of B-vitamins and colorectal cancer risk (CRC). Methods: We interviewed 727 CRC cases of Japanese, Caucasian, or Native Hawaiian origin and 727 controls matched on sex, age, and ethnicity. Results: Compared to the homozygous wild-type genotype, the odds ratios for subjects with one or two MTHFR 677T variant alleles were 0.8 (0.6–1.1) and 0.7 (0.5–1.1), respectively (p for gene–dosage effect: 0.04). The TT genotype was associated with a 50–60% decrease in CRC risk among subjects with high intake of folate or vitamin B6, compared to those with the CC genotype and low levels of intake. The MTHFR 1298C and CBS8 44ins68 variant alleles were also found to be weakly protective against CRC and to act jointly with the 677T allele. Conclusions: This study provides additional evidence for a decreased CRC risk for subjects with the MTHFR 677T allele, particularly at high levels of folate and vitamin B6 intake. Our data also suggest that the relationships between CRC and the MTHFR A1298C and CBS 844ins68 polymorphisms warrant further study.

Cancer Incidence Trends Among Asian American Populations in the United States, 1990–2008

BACKGROUND National cancer incidence trends are presented for eight Asian American groups: Asian Indians/Pakistanis, Chinese, Filipinos, Japanese, Kampucheans, Koreans, Laotians, and Vietnamese. METHODS Cancer incidence data from 1990 through 2008 were obtained from 13 Surveillance, Epidemiology, End Results (SEER) registries. Incidence rates from 1990 through 2008 and average percentage change were computed using SEER*Stat and Joinpoint software. The annual percentage change (APC) in incidence rates was estimated with 95% confidence intervals (95% CIs) calculated for both the rate and APC estimates. Rates for non-Hispanic whites are presented for comparison. RESULTS Prostate cancer was the most common malignancy among most groups, followed by lung, colorectal, liver, and stomach cancers. Breast cancer was generally the most common cancer in women, followed by colorectal and lung cancers; liver, cervix, thyroid, and stomach cancers also ranked highly. Among men, increasing trends were observed for prostate (Asian Indians and Pakistanis: APC 1990-2003 = 2.2, 95% CI = 0.3 to 4.1; Filipinos: APC 1990-1994 = 19.0, 95% CI = 4.5 to 35.4; Koreans: APC 1990-2008 = 2.9, 95% CI = 1.8 to 4.0), colorectal (Koreans: APC 1990-2008 = 2.2, 95% CI = 0.9 to 3.5), and liver cancers (Filipinos: APC 1990-2008 = 1.6, 95% CI = 0.4 to 2.7; Koreans: APC 1990-2006 = 2.1, 95% CI = 0.4 to 3.7; Vietnamese: APC 1990-2008 = 1.6, 95% CI = 0.3 to 2.8), whereas lung and stomach cancers generally remained stable or decreased. Among women, increases were observed for uterine cancer (Asian Indians: APC 1990-2008 = 3.0, 95% CI = 0.3 to 5.8; Chinese: APC 2004-2008 = 7.0, 95% CI = 1.4 to 12.9; Filipina: APC 1990-2008 = 3.0, 95% CI = 2.4 to 3.7; Japanese: APC 1990-2008 = 1.1, 95% CI = 0.1 to 2.0), colorectal cancer (Koreans: APC 1990-2008 = 2.8, 95% CI = 1.7 to 3.9; Laotians: APC: 1990-2008 = 5.9, 95% CI = 4.0 to 7.7), lung cancer (Filipinas: APC 1990-2008 = 2.1, 95% CI = 1.4 to 2.8; Koreans: APC 1990-2008 = 2.1, 95% CI = 0.6 to 3.6), thyroid cancer (Filipinas: APC 1990-2008 = 2.5, 95% CI = 1.7 to 3.3), and breast cancer in most groups (APC 1990-2008 from 1.2 among Vietnamese and Chinese to 4.7 among Koreans). Decreases were observed for stomach (Chinese and Japanese), colorectal (Chinese), and cervical cancers (Laotians and Vietnamese). CONCLUSIONS These data fill a critical knowledge gap concerning the cancer experience of Asian American groups and highlight where increased preventive, screening, and surveillance efforts are needed-in particular, lung cancer among Filipina and Korean women and Asian Indian/Pakistani men, breast cancer among all women, and liver cancer among Vietnamese, Laotian, and Kampuchean women and Filipino, Kampuchean, and Vietnamese men.

Hormone-receptor expression and ovarian cancer survival: an Ovarian Tumor Tissue Analysis consortium study

BACKGROUND Few biomarkers of ovarian cancer prognosis have been established, partly because subtype-specific associations might be obscured in studies combining all histopathological subtypes. We examined whether tumour expression of the progesterone receptor (PR) and oestrogen receptor (ER) was associated with subtype-specific survival. METHODS 12 studies participating in the Ovarian Tumor Tissue Analysis consortium contributed tissue microarray sections and clinical data to our study. Participants included in our analysis had been diagnosed with invasive serous, mucinous, endometrioid, or clear-cell carcinomas of the ovary. For a patient to be eligible, tissue microarrays, clinical follow-up data, age at diagnosis, and tumour grade and stage had to be available. Clinical data were obtained from medical records, cancer registries, death certificates, pathology reports, and review of histological slides. PR and ER statuses were assessed by central immunohistochemistry analysis done by masked pathologists. PR and ER staining was defined as negative (<1% tumour cell nuclei), weak (1 to <50%), or strong (≥50%). Associations with disease-specific survival were assessed. FINDINGS 2933 women with invasive epithelial ovarian cancer were included: 1742 with high-grade serous carcinoma, 110 with low-grade serous carcinoma, 207 with mucinous carcinoma, 484 with endometrioid carcinoma, and 390 with clear-cell carcinoma. PR expression was associated with improved disease-specific survival in endometrioid carcinoma (log-rank p<0·0001) and high-grade serous carcinoma (log-rank p=0·0006), and ER expression was associated with improved disease-specific survival in endometrioid carcinoma (log-rank p<0·0001). We recorded no significant associations for mucinous, clear-cell, or low-grade serous carcinoma. Positive hormone-receptor expression (weak or strong staining for PR or ER, or both) was associated with significantly improved disease-specific survival in endometrioid carcinoma compared with negative hormone-receptor expression, independent of study site, age, stage, and grade (hazard ratio 0·33, 95% CI 0·21-0·51; p<0·0001). Strong PR expression was independently associated with improved disease-specific survival in high-grade serous carcinoma (0·71, 0·55-0·91; p=0·0080), but weak PR expression was not (1·02, 0·89-1·18; p=0·74). INTERPRETATION PR and ER are prognostic biomarkers for endometrioid and high-grade serous ovarian cancers. Clinical trials, stratified by subtype and biomarker status, are needed to establish whether hormone-receptor status predicts response to endocrine treatment, and whether it could guide personalised treatment for ovarian cancer. FUNDING Carraresi Foundation and others.

Consistent Association of Type 2 Diabetes Risk Variants Found in Europeans in Diverse Racial and Ethnic Groups

It has been recently hypothesized that many of the signals detected in genome-wide association studies (GWAS) to T2D and other diseases, despite being observed to common variants, might in fact result from causal mutations that are rare. One prediction of this hypothesis is that the allelic associations should be population-specific, as the causal mutations arose after the migrations that established different populations around the world. We selected 19 common variants found to be reproducibly associated to T2D risk in European populations and studied them in a large multiethnic case-control study (6,142 cases and 7,403 controls) among men and women from 5 racial/ethnic groups (European Americans, African Americans, Latinos, Japanese Americans, and Native Hawaiians). In analysis pooled across ethnic groups, the allelic associations were in the same direction as the original report for all 19 variants, and 14 of the 19 were significantly associated with risk. In summing the number of risk alleles for each individual, the per-allele associations were highly statistically significant (P<10−4) and similar in all populations (odds ratios 1.09–1.12) except in Japanese Americans the estimated effect per allele was larger than in the other populations (1.20; Phet = 3.8×10−4). We did not observe ethnic differences in the distribution of risk that would explain the increased prevalence of type 2 diabetes in these groups as compared to European Americans. The consistency of allelic associations in diverse racial/ethnic groups is not predicted under the hypothesis of Goldstein regarding “synthetic associations” of rare mutations in T2D.