Family history of colorectal cancer is not associated with colorectal cancer survival regardless of microsatellite instability status

BACKGROUND

Individuals with a family history of colorectal cancer in first-degree relatives have an elevated risk of developing colorectal cancer themselves, particularly colorectal cancer exhibiting high microsatellite instability (MSI-high). Given that MSI-high colorectal cancer is associated with a favorable prognosis, it is plausible that having a family history of colorectal cancer could, in turn, be favorably associated with colorectal cancer survival.

METHODS

This study comprised N = 4,284 incident colorectal cancer cases enrolled in the Colon Cancer Family Registry via population-based cancer registries. Using Cox proportional hazards regression, we evaluated the association between family history and both overall and disease-specific survival, accounting for MSI status and tumor site via stratified analyses and statistical adjustment.

RESULTS

There was no evidence of association between family history and overall [hazard ratio (HR), 0.92; 95% confidence interval (CI), 0.79-1.08] or disease-specific survival (HR, 1.03; 95% CI, 0.85-1.24) for all cases combined, after adjustment for MSI status or tumor site. Only for rectal cancer cases was colorectal cancer family history modestly associated with more favorable overall survival (HR, 0.75; 95% CI, 0.56-0.99).

CONCLUSIONS

Although individuals with a family history of colorectal cancer were more likely to have MSI-high tumors than those with nonfamilial disease, this did not translate to a survival benefit.

IMPACT

Overall, there is no evidence that family history of colorectal cancer is associated with colorectal cancer survival; however, specific mechanisms underlying family history may have prognostic impact and merit further study.

Dietary cadmium exposure and risk of breast, endometrial, and ovarian cancer in the Women's Health Initiative

BACKGROUND

In vitro and animal data suggest that cadmium, a heavy metal that contaminates some foods and tobacco plants, is an estrogenic endocrine disruptor. Elevated estrogen exposure is associated with breast, endometrial, and ovarian cancer risk.

OBJECTIVES

We examined the association between dietary cadmium intake and risk of these cancers in the large, well-characterized Women's Health Initiative (WHI).

METHODS

A total of 155,069 postmenopausal women, 50-79 years of age, who were enrolled in the WHI clinical trials or observational study, participated in this study. We estimated dietary cadmium consumption by combining baseline food frequency questionnaire responses with U.S. Food and Drug Administration data on food cadmium content. Participants reported incident invasive breast, endometrial, or ovarian cancer, and WHI centrally adjudicated all cases through August 2009. We applied Cox regression to estimate adjusted hazard ratios (HRs) and 95% CIs for each cancer, comparing quintiles of energy-adjusted dietary cadmium intake.

RESULTS

Over an average of 10.5 years, 6,658 invasive breast cancers, 1,198 endometrial cancers, and 735 ovarian cancers were reported. We observed no statistically significant associations between dietary cadmium and risk of any of these cancers after adjustment for potential confounders including total dietary energy intake. Results did not differ in any subgroup of women examined.

CONCLUSIONS

We found little evidence that dietary cadmium is a risk factor for breast, endometrial, or ovarian cancers in postmenopausal women. Misclassification in dietary cadmium assessment may have attenuated observed associations.

Pleiotropic effects of genetic risk variants for other cancers on colorectal cancer risk: PAGE, GECCO and CCFR consortia

OBJECTIVE

Genome-wide association studies have identified a large number of single nucleotide polymorphisms (SNPs) associated with a wide array of cancer sites. Several of these variants demonstrate associations with multiple cancers, suggesting pleiotropic effects and shared biological mechanisms across some cancers. We hypothesised that SNPs previously associated with other cancers may additionally be associated with colorectal cancer. In a large-scale study, we examined 171 SNPs previously associated with 18 different cancers for their associations with colorectal cancer.

DESIGN

We examined 13 338 colorectal cancer cases and 40 967 controls from three consortia: Population Architecture using Genomics and Epidemiology (PAGE), Genetic Epidemiology of Colorectal Cancer (GECCO), and the Colon Cancer Family Registry (CCFR). Study-specific logistic regression results, adjusted for age, sex, principal components of genetic ancestry, and/or study specific factors (as relevant) were combined using fixed-effect meta-analyses to evaluate the association between each SNP and colorectal cancer risk. A Bonferroni-corrected p value of 2.92×10(-4) was used to determine statistical significance of the associations.

RESULTS

Two correlated SNPs--rs10090154 and rs4242382--in Region 1 of chromosome 8q24, a prostate cancer susceptibility region, demonstrated statistically significant associations with colorectal cancer risk. The most significant association was observed with rs4242382 (meta-analysis OR=1.12; 95% CI 1.07 to 1.18; p=1.74×10(-5)), which also demonstrated similar associations across racial/ethnic populations and anatomical sub-sites.

CONCLUSIONS

This is the first study to clearly demonstrate Region 1 of chromosome 8q24 as a susceptibility locus for colorectal cancer; thus, adding colorectal cancer to the list of cancer sites linked to this particular multicancer risk region at 8q24.

Risk of colorectal cancer for carriers of mutations in MUTYH, with and without a family history of cancer

We studied 2332 individuals with monoallelic mutations in MUTYH among 9504 relatives of 264 colorectal cancer (CRC) cases with a MUTYH mutation. We estimated CRC risks through 70 years of age of 7.2% for male carriers of monoallelic mutations (95% confidence interval [CI], 4.6%-11.3%) and 5.6% for female carriers of monoallelic mutations (95% CI, 3.6%-8.8%), irrespective of family history. For monoallelic MUTYH mutation carriers with a first-degree relative with CRC diagnosed by 50 years of age who does not have the MUTYH mutation, risks of CRC were 12.5% for men (95% CI, 8.6%-17.7%) and 10% for women (95% CI, 6.7%-14.4%). Risks of CRC for carriers of monoallelic mutations in MUTYH with a first-degree relative with CRC are sufficiently high to warrant more intensive screening than for the general population.

Genetic variation in UGT genes modify the associations of NSAIDs with risk of colorectal cancer: colon cancer family registry

The use of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with reduced risk of colorectal neoplasia. Previous studies have reported that polymorphisms in NSAID-metabolizing enzymes central to NSAID metabolism including UDP-glucuronosyltransferases (UGT) and cytochrome P450 (CYP) 2C9 may modify this protective effect. We investigated whether 35 functionally relevant polymorphisms within CYP2C9 and UGT genes were associated with colorectal cancer risk or modified the protective effect of NSAIDs on colorectal cancer susceptibility, using 1,584 colorectal cancer cases and 2,516 unaffected sibling controls from the Colon Cancer Family Registry. A three-SNP genotype in UGT1A6 (G-A-A; Ala7-Thr181-Arg184) and the Asp85 variant in UGT2B15 increased the risk of colorectal cancer (OR 3.87; 95% CI 1.04-14.45 and OR 1.34; 95% CI 1.10-1.63, respectively). We observed interactions between UGT1A3 Thr78Thr (A>G) and NSAID use (P-interaction = 0.02), a three-SNP genotype within UGT2B4 and ibuprofen use (P-interaction = 0.0018), as well as UGT2B15 Tyr85Asp (T>G) and aspirin use (P-interaction = 0.01). The interaction with the UGT2B4 and the UGT2B15 polymorphisms were noteworthy at the 25% FDR level. This study highlights the need for further pharmacogenetic studies to identify individuals who might benefit from NSAID use as part of developing effective strategies for prevention of colorectal neoplasia. © 2014 Wiley Periodicals, Inc.

Modification of breast cancer risk according to age and menopausal status: a combined analysis of five population-based case-control studies

While several risk factors for breast cancer have been identified, studies have not consistently shown whether these factors operate more strongly at certain ages or for just pre- or postmenopausal women. We evaluated whether risk factors for breast cancer differ according to age or menopausal status. Data from five population-based case-control studies conducted during 1988-2008 were combined and analyzed. Cases (N = 23,959) and population controls (N = 28,304) completed telephone interviews. Logistic regression was used to estimate adjusted odds ratios and 95 % confidence intervals and tests for interaction by age and menopausal status. Odds ratios for first-degree family history of breast cancer were strongest for younger women-reaching twofold elevations-but were still statistically significantly elevated by 58-69 % among older women. Obesity was inversely associated with breast cancer among younger women and positively associated with risk for older women (interaction P < 0.0001). Recent alcohol intake was more strongly related to breast cancer risk among older women, although consumption of 3 or more drinks/day among younger women also was associated with elevated odd ratios (P < 0.0001). Associations with benign breast disease and most reproductive/menstrual factors did not vary by age. Repeating analysis stratifying by menopausal status produced similar results. With few exceptions, menstrual and lifestyle factors are associated with breast cancer risk regardless of age or menopausal status. Variation in the association of family history, obesity, and alcohol use with breast cancer risk by age and menopausal status may need to be considered when determining individual risk for breast cancer.

Does risk of endometrial cancer for women without a germline mutation in a DNA mismatch repair gene depend on family history of endometrial cancer or colorectal cancer?

OBJECTIVE

To determine whether risk of endometrial cancer for women without a germline mutation in a DNA mismatch repair (MMR) gene depends on family history of endometrial or colorectal cancer.

METHODS

We retrospectively followed a cohort of 79,166 women who were recruited to the Colon Cancer Family Registry, after exclusion of women who were relatives of a carrier of a MMR gene mutation. The Kaplan-Meier failure method was used to estimate the cumulative risk of endometrial cancer. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for association between family history of endometrial or colorectal cancer and risk of endometrial cancer.

RESULTS

A total of 628 endometrial cancer cases were observed, with mean age at diagnosis of 54.4 (standard deviation: 15.7) years. The cumulative risk of endometrial cancer to age 70 years was estimated to be 0.94% (95% CI 0.83-1.05) for women with no family history of endometrial cancer, and 3.80% (95% CI 2.75-4.98) for women with at least one first- or second-degree relative with endometrial cancer. Compared with women without family history, we found an increased risk of endometrial cancer for women with at least one first- or second-degree relative with endometrial cancer (HR 3.66, 95% CI 2.63-5.08), and for women with one first-degree relative with colorectal cancer diagnosed at age <50 years (HR 1.48, 95% CI 1.15-1.91).

CONCLUSION

An increased risk of endometrial cancer is associated with a family history of endometrial cancer or early-onset colorectal cancer for women without a MMR gene mutation, indicating for potential underlying genetic and environmental factors shared by colorectal and endometrial cancers other than caused by MMR gene mutations.

Reproductive windows, genetic loci, and breast cancer risk

PURPOSE

The reproductive windows between age at menarche and age at first birth (standardized age at first birth) and from menarche to menopause (reproductive lifespan) may interact with genetic variants in association with breast cancer risk.

METHODS

We assessed this hypothesis in 6131 breast cancer cases and 7274 controls who participated in the population-based Collaborative Breast Cancer Study. Risk factor information was collected through telephone interviews, and DNA samples were collected on a subsample (N= 1484 cases, 1307 controls) to genotype for 13 genome-wide association study-identified loci. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated, and P values for the interaction between reproductive windows and genotypes were obtained by adding cross-product terms to statistical models.

RESULTS

For standardized age at first birth, the OR was 1.52 (CI, 1.36-1.71) comparing the highest quintile with the lowest quintile. Carrier status for rs10941679 (5p12) and rs10483813 (RAD51B) appeared to modify this relationship (P = .04 and P = .02, respectively). For reproductive lifespan, the OR comparing the highest quintile with the lowest quintiles was 1.62 (CI, 1.35-1.95). No interactions were detected between genotype and reproductive lifespan (all P > .05). All results were similar regardless of ductal versus lobular breast cancer subtype.

CONCLUSIONS

Our results suggest that the reproductive windows are associated with breast cancer risk and that associations may vary by genetic variants.

Cadmium blood and urine concentrations as measures of exposure: NHANES 1999-2010

Exposure to cadmium, a heavy metal present in cigarettes, can be assessed in both urine and blood. Few studies have compared the properties of concurrent measurements of urine cadmium (uCd) and blood cadmium (bCd) in relation to the duration and timing of a known exposure. In this study, bCd and uCd were modeled with data from the National Health and Nutrition Examination Survey (1999-2010). Adjusted geometric mean bCd and uCd were estimated from regression results. Each 1% higher geometric mean uCd was associated with 0.50% (95% confidence interval: 0.47%-0.54%; R(2)=0.30) higher bCd. In male never-smokers, bCd was 69% (59%-81%) and uCd was 200% (166%-234%) higher at age ≥70 years versus 20-29 years. Ten pack-years (py) of smoking were associated with 13.7% (10.0%-17.4%) higher bCd and 16.8% (12.6%-21.1%) higher uCd in male smokers. The first year after smoking cessation was associated with 53% (48%-58%) lower bCd and 23% (14%-33%) lower uCd in representative males aged 55 years with 20 py smoking. Smoking in the previous 5 days was associated with 55% (40%-71%) higher bCd and 7% (-3%-18%) higher uCd. Results were similar for women. uCd mainly measures long-term exposure and bCd recent exposure, but with noticeable overlap. Epidemiological studies should base the choice of uCd or bCd on the timing of cadmium exposure relevant to the disease under study.

Smoking History in Relation to Survival after a Breast Cancer Diagnosis

Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.

A randomized trial to increase colonoscopy screening in members of high-risk families in the colorectal cancer family registry and cancer genetics network

BACKGROUND

Individuals with a strong family history of colorectal cancer have significant risk for colorectal cancer, although adherence to colonoscopy screening in these groups remains low. This study assessed whether a tailored telephone counseling intervention can increase adherence to colonoscopy in members of high-risk families in a randomized, controlled trial.

METHODS

Eligible participants were recruited from two national cancer registries if they had a first-degree relative with colorectal cancer under age 60 or multiple affected family members, which included families that met the Amsterdam criteria for hereditary non-polyposis colon cancer (HNPCC), and if they were due for colonoscopy within 24 months. Participants were randomized to receive a tailored telephone intervention grounded in behavioral theory or a mailed packet with general information about screening. Colonoscopy status was assessed through follow-up surveys and endoscopy reports. Cox proportional hazards models were used to assess intervention effect.

RESULTS

Of the 632 participants (ages 25-80), 60% were female, the majority were White, non-Hispanic, educated, and had health insurance. Colonoscopy adherence increased 11 percentage points in the tailored telephone intervention group, compared with no significant change in the mailed group. The telephone intervention was associated with a 32% increase in screening adherence compared with the mailed intervention (HR, 1.32; P = 0.01).

CONCLUSIONS

A tailored telephone intervention can effectively increase colonoscopy adherence in high-risk persons. This intervention has the potential for broad dissemination to healthcare organizations or other high-risk populations.

IMPACT

Increasing adherence to colonoscopy among persons with increased colorectal cancer risk could effectively reduce incidence and mortality from this disease.

Molecular subtypes of colorectal cancer in relation to disease survival

451

Background: Classifications for molecular subtypes of colorectal cancer based on microsatellite instability (MSI), the CpG island methylator phenotype (CIMP), and somatic mutations in BRAFV600E and KRAS have been proposed to reflect distinct pathways of colorectal tumorigenesis. We assessed the relationship between these subtype classifications and colorectal cancer survival in a population-based study. Methods: Tumor-markers were evaluated in incident colorectal cancer cases diagnosed between 1997-2007 in western Washington State. Cases were classified into pathway-based subtypes according to the following tumor-marker combinations: (1) traditional pathway [microsatellite stable / low MSI (MSS/MSI-L), non-CIMP, BRAF-wildtype, KRAS-wildtype, n = 631]; (2) MSI-high serrated (MSI-high, CIMP-positive, BRAF-mutated, KRAS-wildtype, N=100); (3) MSS/MSI-L serrated (MSS/MSI-L, CIMP-positive, BRAF-mutated, KRAS-wildtype, n = 55); (4) alternate pathway (MSS/MSI-L, non-CIMP, BRAF-wildtype, KRAS-mutated, n = 353); and (5) MSI-high familial (MSI-high, non-CIMP, BRAF-wildtype, KRAS-wildtype, n = 50). Multiple-imputation was used to classify tumor-marker status for cases with missing data on one to three markers. Differences in survival across subtypes were assessed through multivariable-adjusted Cox regression. Results: Relative to cases of the predominant traditional pathway subtype, cases with MSS/MSI-L serrated and alternate pathway tumor subtypes experienced statistically significantly worse disease-specific survival [hazard ratio (HR) = 2.25, 95% confidence interval (CI): 1.50-3.36 and HR = 1.39, 95% CI: 1.12-1.71, respectively]; cases with MSI-high familial tumors had the most favorable disease-specific prognosis (HR = 0.28, 95% CI: 0.12-0.64). With respect to overall survival, associations were similar but slightly attenuated. Conclusions: In this large, population-based study, colorectal cancer subtype classifications based on integrated pathways were associated with marked differences in survival, highlighting the significance of molecular heterogeneity in colorectal cancer.

DCC and RET pathway analysis to identify factors associated with advanced colorectal cancer

457

Background: DCC (deleted in colon cancer; 18q21.3) is frequently lost in colorectal cancers (CRC), but few mutations in DCC have been discovered, even in tumors with 18q loss of heterozygosity. DCC has been shown to be a dependence receptor, with differential signaling depending on the presence (proliferative) or absence (pro-apoptotic) of the netrin-1 ligand (NTN1). DCC-mutated CRC tend to present at advanced stage and have a poor prognosis. RET, another dependence receptor, is a possible tumor suppressor gene in CRC and associates with CRC progression. Given the apparent role of DCC and RET in CRC progression, we carried out a genetic association study to determine if specific genetic variants in these pathways associate with advanced vs. early CRC. Methods: Imputed HapMap genome-wide association study (GWAS) from the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), a collection of 19 international case-control and cohort studies, was used to identify single nucleotide polymorphisms (SNPs) in DCC, NTN1, RET and interacting genes within 5kb upstream to 500mb downstream of each of the 54 genes. With the resultant 10,102 SNPs, we performed a stage-stratified analysis, comparing advanced (AJCC stage III-IV, n = 3500) to early CRC (I-II, n = 5300). An inverse-variance weighted fixed effect meta-analysis was performed with significance set at p=0.05/10102 SNPs=5x10-6 for multiple test correction. Results: Of the examined SNPs within DCC, the lowest p-value comparing advanced vs. early CRC was 3.6x10-3. SNPs in DOCK1 (dedicator of cytokinesis 1), which complexes with DCC and netrin-1, were associated with advanced CRC at p=1.11x10-3. SNPs in NTN1 and RET reached significance only at p = 1.73x10-2 and 1.53x10-2, respectively. No SNPs reached the pre-determined level of statistical significance. Conclusions: Our current analysis does not provide clear evidence for candidate SNPs associated with advanced CRC. Further approaches include expanding the analysis to include 1,000 Genome Project and ExomeChip data (~30,000 added SNPs), comparison of cases and controls, and evaluating candidate SNP-SNP interactions to better evaluate pathway pathogenesis. We plan to present an updated analysis at the symposium.

Lifestyle factors and the risk of a second breast cancer after ductal carcinoma in situ

BACKGROUND

Little information exists on lifestyle factors that affect prognosis after treatment for ductal carcinoma in situ (DCIS) breast cancer. Improved understanding of the role of lifestyle factors is important to survivors wishing to reduce their risk of a second breast cancer diagnosis.

METHODS

We examined the association between body mass index (BMI), physical activity, and alcohol intake, and risk of a second breast cancer diagnosis among 1,925 DCIS survivors in the Wisconsin In Situ Cohort. Exposures were self-reported during biennial patient interviews. Second breast cancer diagnoses were validated via pathology report. Cox proportional hazards regression was used to estimate the association between prediagnosis, postdiagnosis, and change in exposure levels and the risk of a second diagnosis, with adjustment for patient, tumor, and treatment factors.

RESULTS

Over a mean of 6.7 years of follow-up, 162 second breast cancer diagnoses were reported, including 57 invasive events, 60 in situ events, and 45 diagnoses of unknown stage. A significant trend of increasing risk of a second diagnosis was found over increasing categories of postdiagnosis alcohol intake (Ptrend = 0.02). Among premenopausal women, increased prediagnosis BMI was associated with a reduced risk of a second diagnosis (HR = 0.93; 95% confidence interval, 0.88-0.99).

CONCLUSION

DCIS survivors may reduce their risk of a second diagnosis by reducing postdiagnosis alcohol consumption.

IMPACT

The population of DCIS survivors is projected to surpass one million by the year 2016. Our results suggest that these women may be able to reduce their risk of a second diagnosis through moderation of alcohol consumption.

Breast cancer susceptibility loci in association with age at menarche, age at natural menopause and the reproductive lifespan

BACKGROUND

Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) associated with breast cancer risk. Some of these loci have unknown functional significance and may mediate the effects of hormonal exposures on breast cancer risk. We examined relationships between breast cancer susceptibility variants and menstrual/reproductive factors using data from two population-based studies.

METHODS

The first analysis was based on a sample of 1328 women age 20-74 who participated as controls in a case-control study of breast cancer conducted in three U.S. states. We evaluated the associations between age at menarche, age at natural menopause and the reproductive lifespan with 13 previously identified breast cancer variants. Associations were also examined with a genetic score created as the sum of at-risk alleles across the 13 variants. For validation, significant results were evaluated in a second dataset comprised 1353 women age 43-86 recruited as part of a cohort study in Wisconsin.

RESULTS

Neither the genetic score nor any of the 13 variants considered individually were associated with age at menarche or reproductive lifespan. Two SNPs were associated with age at natural menopause; every increase in the minor allele (A) of rs17468277 (CASP8) was associated with a 1.12 year decrease in menopause age (p=0.02). The minor allele (G) of rs10941679 (5p12) was associated with a 1.01 year increase in age at natural menopause (p=0.01). The results were not replicated in the validation cohort (B=-0.61, p=0.14 and B=-0.01, p=.0.98, respectively).

CONCLUSIONS

The evaluated variants and reproductive experiences may work through separate pathways to influence breast cancer risk.

Abstract P1-06-06: Alteration of stromal collagen fiber orientation in DCIS

Approximately 20% of new diagnoses of breast cancer are ductal carcinoma in situ (DCIS), a non-invasive form of breast cancer. Treatment decision-making for DCIS is challenging since current predictors of disease-free survival are limited, so that most women are presented with options for surgery, radiation and tamoxifen - all options with consequences for quality of life. Prior studies of prognostic factors for DCIS have focused on morphologic, genetic, and protein expression patterns of the DCIS cells. However, laboratory evidence suggests that the tumor microenvironment may play a key role in tumor invasion and progression. Collagen is the most abundant component of the stroma surrounding the breast ducts in which cancers develop. We previously observed that, in invasive breast cancer, tumors with greater numbers of collagen fibers aligned perpendicularly from the tumor were more likely to predict poor survival than tumors with collagen fibers in primarily parallel patterns near the tumor boundary (Conklin Am J Pathol 2011). To improve our ability to predict breast cancer outcomes in women with DCIS, we examined the alignment of collagen adjacent to ducts affected by DCIS to test whether alignment patterns were similar to patterns observed in tissue labeled as “normal” from biopsy and surgical sections. We evaluated collagen alignment in 255 Wisconsin women diagnosed with DCIS in 1997-2000 and followed for a median of 11.2 years (range 1-15). Stromal collagen alignment was evaluated from routine H&E tissue slides prepared at the time of diagnosis using second harmonic generation (SHG) microscopy, a label-free multiphoton laser scanning technique that selectively images collagen. SHG images were acquired and evaluated for 3-5 regions on each DCIS and normal slide for each patient; the angles of collagen fibers with respect to the DCIS lesion/stroma boundary were calculated using customized imaging software. Data for the distribution of angles were compared for normal ducts and DCIS lesions using compositional data analysis with the number of fibers totaled according to 5-angle bins (1-5, 6-10, 11-15, …, 86-90 degrees). Repeated measures linear regression models were fit to log-transformed ratios of binned counts as a function of tissue type. Dependence among repeated counts within a single region was modeled using an unstructured variance-covariance matrix. Dependence among measurements within a single subject was modeled using a compound symmetry correlation structure. Overall, the distribution of collagen fiber angles from DCIS lesions differed significantly (P = 0.0002) from the distribution of collagen fibers surrounding normal ducts. Collagen fibers surrounding DCIS lesions were 11-18% more likely to orient at 75-90 degrees relative to the lesion boundary than fibers surrounding normal ducts; fibers were more similarly aligned in both DCIS lesions and normal ducts at other smaller angles. These results underscore the relevance of the tumor microenvironment, in particular the arrangement of the collagen fiber matrix. Planned data analysis will next examine whether collagen fiber alignment patterns differ between DCIS patients who did and did not experience a second breast cancer diagnosis over the course of follow-up.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-06-06.

Deciphering the genetic architecture of low-penetrance susceptibility to colorectal cancer

Recent genome-wide association studies (GWASs) have identified common variants at 16 autosomal regions influencing the risk of developing colorectal cancer (CRC). To decipher the genetic basis of the association signals at these loci, we performed a meta-analysis of data from five GWASs, totalling 5626 cases and 7817 controls, using imputation to recover un-typed genotypes. To enhance our ability to discover low-frequency risk variants, in addition to using 1000 Genomes Project data as a reference panel, we made use of high-coverage sequencing data on 253 individuals, 199 with early-onset familial CRC. For 13 of the regions, it was possible to refine the association signal identifying a smaller region of interest likely to harbour the functional variant. Our analysis did not provide evidence that any of the associations at the 16 loci being a consequence of synthetic associations rather than linkage disequilibrium with a common risk variant.

Descriptive profile of PIK3CA-mutated colorectal cancer in postmenopausal women

PURPOSE

Approximately 10-30 % of colorectal cancers exhibit somatic mutations in the phosphoinositide-3-kinase, catalytic, alpha polypeptide gene (PIK3CA). We evaluated the relationship between PIK3CA mutation status and demographic factors, lifestyle factors, and other tumor characteristics and the relationship between PIK3CA mutation status and colorectal cancer survival.

METHODS

The population-based study included postmenopausal women with invasive colorectal cancer diagnosed between 1998 and 2002 in Western Washington State. Participants were interviewed, and tumor specimens were tested for PIK3CA mutations in exons 9 and 20 hotspots, KRAS exon 2 mutations, BRAF p.V600E mutation, and microsatellite instability. We used Cox regression to evaluate the association between PIK3CA mutation status and disease-specific and overall survival. Stratified analyses were conducted by KRAS mutation status.

RESULTS

PIK3CA mutations were evident in approximately 13 % of cases (N = 35). Women with PIK3CA-mutated colorectal cancer were significantly more likely than those with PIK3CA wild-type disease to be non-white, to have proximal colon cancer, and to have KRAS-mutated tumors (p < 0.05). In Cox proportional hazards regression analyses, overall survival was poorer, although not statistically significantly so, for women with PIK3CA-mutated versus wild-type colorectal cancer (hazard ratio = 1.74, 95 % confidence interval 0.86-3.50). This association between PIK3CA mutation status and survival was evident only when analyses were restricted to cases without somatic KRAS mutations (hazard ratio = 2.94, 95 % confidence interval 1.12-7.73).

CONCLUSIONS

PIK3CA-mutated colorectal cancer appears to have a distinct epidemiologic profile that is of clinical significance. Women with PIK3CA-mutated colorectal cancer experience a poorer prognosis than those with PIK3CA wild-type disease.

Genetic variation in the inflammation and innate immunity pathways and colorectal cancer risk

BACKGROUND

It is widely accepted that chronic inflammation plays a role in the etiology of colorectal cancer. Using a two-stage design, we examined the associations between colorectal cancer and common variation in 37 key genes in the inflammation and innate immunity pathways.

METHODS

In the discovery stage, 2,322 discordant sibships (2,535 cases, 3,915 sibling controls) from the Colorectal Cancer Family Registry were genotyped for more than 600 tagSNPs and 99 single-nucleotide polymorphisms (SNP) were selected for further examination based on strength of association. In the second stage, 351 SNPs tagging gene regions covered by the 99 SNPs were tested in 4,783 Multiethnic Cohort subjects (2,153 cases, 2,630 controls).

RESULTS

The association between rs9858822 in the PPARG gene and colorectal cancer was statistically significant at the end of the second stage (OR per allele = 1.36, Bonferroni-adjusted P = 0.045), based on the "effective" number of markers in stage II (n = 306). The risk allele C was common (frequency 0.3) in African Americans but rare (frequency < 0.03) in whites, Japanese Americans, Latinos, and Native Hawaiians. No statistically significant heterogeneity of effects across race/ethnicity, body mass index (BMI) levels, regular aspirin use, or pack-years of smoking was detected for this SNP. Suggestive associations were also observed for several SNPs in close vicinity to rs9858822.

CONCLUSIONS

Our results provide new evidence of association between PPARG variants and colorectal cancer risk.

IMPACT

Further replication in independent samples is warranted.

Oral bisphosphonate use and colorectal cancer incidence in the Women's Health Initiative

Bisphosphonates are widely prescribed to increase bone density in postmenopausal women with osteopenia or osteoporosis. Aminobisphosphonates have numerous anticancer properties and reduce bone metastases in cancer patients. Several studies, including the Women's Health Initiative (WHI), have found that use of oral bisphosphonates is associated with reduced risk of developing breast cancer, but less is known about associations with other common malignancies in women such as colorectal cancer (CRC). A few case-control and retrospective cohort studies have reported decreased risk of CRC among bisphosphonate users. In contrast, a prospective cohort study found no association. We evaluated the association between oral bisphosphonate use and CRC incidence in 156,826 postmenopausal women, ages 50 to 79 years, who participated in WHI clinical trials and observational study. A detailed health interview was conducted at baseline, and bisphosphonate use was ascertained from an inventory of regularly used medications at baseline and over follow-up. A total of 1931 women were diagnosed with incident invasive CRC during a median follow-up of 12 years. Alendronate was the most commonly used bisphosphonate, accounting for >90% of the total person-years of use. The association between oral bisphosphonate use and CRC risk did not reach statistical significance (hazard ratio [HR] from multivariable-adjusted models = 0.88; 95% confidence interval [CI] 0.72-1.07; p = 0.19). Furthermore, we did not observe greater risk reductions for women with longer duration of use. Uncontrolled confounding may explain why previous studies have observed an association.

Genetic predictors of circulating 25-hydroxyvitamin d and risk of colorectal cancer

BACKGROUND

Experimental evidence has demonstrated an antineoplastic role for vitamin D in the colon, and higher circulating 25-hydroxyvitamin D [25(OH)D] levels are consistently associated with a lower risk of colorectal cancer. Genome-wide association studies have identified loci associated with levels of circulating 25(OH)D. The identified single-nucleotide polymorphisms (SNPs) from four gene regions collectively explain approximately 5% of the variance in circulating 25(OH)D.

METHODS

We investigated whether five polymorphisms in GC, CYP2R1, CYP24A1, and DHCR7/NADSYN1, genes previously shown to be associated with circulating 25(OH)D levels, were associated with colorectal cancer risk in 10,061 cases and 12,768 controls drawn from 13 studies included in the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO) and Colon Cancer Family Registry (CCFR). We conducted a meta-analysis of crude and multivariate-adjusted logistic regression models to calculate odds ratios and associated confidence intervals for SNPs individually, SNPs simultaneously, and for a vitamin D additive genetic risk score (GRS).

RESULTS

We did not observe a statistically significant association between the 25(OH)D-associated SNPs and colorectal cancer marginally, conditionally, or as a GRS, or for colon or rectal cancer separately.

CONCLUSIONS

Our findings do not support an association between SNPs associated with circulating 25(OH)D and risk of colorectal cancer. Additional work is warranted to investigate the complex relationship between 25(OH)D and colorectal cancer risk.

IMPACT

There was no association observed between genetic markers of circulating 25(OH)D and colorectal cancer. These genetic markers account for a small proportion of the variance in 25(OH)D.

Disease-free survival by treatment after a DCIS diagnosis in a population-based cohort study

Randomized trials have demonstrated the efficacy of radiation and tamoxifen in reducing risk of second events after breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS), but the comparative effectiveness of mastectomy, BCS, and adjuvant treatments have not been established in community practice. We examined disease-free survival (DFS) among 1,676 DCIS cases diagnosed during 1995-2006 in the population-based Wisconsin In Situ Cohort study. Information on patient and tumor characteristics, treatments, and second breast cancer events were collected via a comprehensive review of data from patient interviews, the statewide cancer registry, and pathology reports. Breast cancer DFS was evaluated according to treatment while adjusting for patient and tumor characteristics. After an average of 7.1 years of follow-up, 143 second breast cancer events occurred. Overall 5-year DFS was similar among women treated with ipsilateral mastectomy (95.6 %; 95 % CI 93.5-97.0) compared to women treated with BCS and radiation (94.8 %; 95 % CI 92.8-96.1), though women receiving BCS without radiation experienced poorer overall DFS (87.0 %; 95 % CI 80.6-91.5). Women treated with tamoxifen in addition to BCS and radiation had a similar risk of a second breast event, although the hazard ratio (HR) suggested a potential benefit (0.70, 95% CI 0.41-1.19). Women treated with BCS, radiation, and tamoxifen had comparable risk of a second event as those treated with ipsilateral mastectomy (HR = 1.20; 95 % CI 0.71-2.02). In this population-based sample, the use of BCS with radiation and tamoxifen resulted in high DFS rates comparable to those achieved by ipsilateral mastectomy.

Cancer risks for MLH1 and MSH2 mutation carriers

We studied 17,576 members of 166 MLH1 and 224 MSH2 mutation-carrying families from the Colon Cancer Family Registry. Average cumulative risks of colorectal cancer (CRC), endometrial cancer (EC), and other cancers for carriers were estimated using modified segregation analysis conditioned on ascertainment criteria. Heterogeneity in risks was investigated using a polygenic risk modifier. Average CRC cumulative risks at the age of 70 years (95% confidence intervals) for MLH1 and MSH2 mutation carriers, respectively, were estimated to be 34% (25%-50%) and 47% (36%-60%) for male carriers and 36% (25%-51%) and 37% (27%-50%) for female carriers. Corresponding EC risks were 18% (9.1%-34%) and 30% (18%-45%). A high level of CRC risk heterogeneity was observed (P < 0.001), with cumulative risks at the age of 70 years estimated to follow U-shaped distributions. For example, 17% of male MSH2 mutation carriers have estimated lifetime risks of 0%-10% and 18% have risks of 90%-100%. Therefore, average risks are similar for the two genes but there is so much individual variation about the average that large proportions of carriers have either very low or very high lifetime cancer risks. Our estimates of CRC and EC cumulative risks for MLH1 and MSH2 mutation carriers are the most precise currently available.