Familial risks in cervical cancer: is there a hereditary component?

Genetic variation in cervical preinvasive and invasive disease: a genome-wide association study

BACKGROUND

Most uterine cervical high-risk human papillomavirus (HPV) infections are transient, with only a small fraction developing into cervical cancer. Family aggregation studies and heritability estimates suggest a significant inherited genetic component. Candidate gene studies and previous genome-wide association studies (GWASs) report associations between the HLA region and cervical cancer. Adopting a genome-wide approach, we aimed to compare genetic variation in women with invasive cervical cancer and cervical intraepithelial neoplasia (CIN) grade 3 with that in healthy controls.

METHODS

We did a GWAS in a cohort of unrelated European individuals using data from UK Biobank, a population-based cohort including 273 377 women aged 40-69 years at recruitment between March 13, 2006, and Oct 1, 2010. We used an additive univariate logistic regression model to analyse genetic variants associated with invasive cervical cancer or CIN3. We sought replication of candidate associations in FinnGen, a large independent dataset of 128 123 individuals. We also did a two-sample mendelian randomisation approach to explore the role of risk factors in the genetic risk of cervical cancer.

FINDINGS

We included 4769 CIN3 and invasive cervical cancer case samples and 145 545 control samples in the GWAS. Of 9 600 464 assayed and imputed single-nucleotide polymorphisms (SNPs), six independent variants were associated with CIN3 and invasive cervical cancer. These included novel loci rs10175462 (PAX8; odds ratio [OR] 0·87, 95% CI 0·84-0·91; p=1·07 × 10-9) and rs27069 (CLPTM1L; 0·88, 0·84-0·92; p=2·51 × 10-9), and previously reported signals at rs9272050 (HLA-DQA1; 1·27, 1·21-1·32; p=2·51 × 10-28), rs6938453 (MICA; 0·79, 0·75-0·83; p=1·97 × 10-17), rs55986091 (HLA-DQB1; 0·66, 0·60-0·72; p=6·42 × 10-28), and rs9266183 (HLA-B; 0·73, 0·64-0·83; p=1·53 × 10-6). Three SNPs were replicated in the independent Finnish dataset of 1648 invasive cervical cancer cases: PAX8 (rs10175462; p=0·015), CLPTM1L (rs27069; p=2·54 × 10-7), and HLA-DQA1 (rs9272050; p=7·90 × 10-8). Mendelian randomisation further supported the complementary role of smoking (OR 2·46, 95% CI 1·64-3·69), older age at first pregnancy (0·80, 0·68-0·95), and number of sexual partners (1·95, 1·44-2·63) in the risk of developing cervical cancer.

INTERPRETATION

Our results provide new evidence for the genetic susceptibility to cervical cancer, specifically the PAX8, CLPTM1L, and HLA genes, suggesting disruption in apoptotic and immune function pathways. Future studies integrating host and viral, genetic, and epigenetic variation, could further elucidate complex host-viral interactions.

FUNDING

NIHR Imperial BRC Wellcome 4i Clinician Scientist Training Programme.

Mucosal and Cutaneous Human Papillomavirus Infections and Cancer Biology

Papillomaviridae is a family of small non-enveloped icosahedral viruses with double-stranded circular DNA. More than 200 different human papillomaviruses (HPVs) have been listed so far. Based on epidemiological data, a subgroup of alphapapillomaviruses (alpha HPVs) was referred to as high-risk (HR) HPV types. HR HPVs are the etiological agents of anogenital cancer and a subset of head and neck cancers. The cutaneous HPV types, mainly from beta and gamma genera, are widely present on the surface of the skin in the general population. However, there is growing evidence of an etiological role of betapapillomaviruses (beta HPVs) in non-melanoma skin cancer (NMSC), together with ultraviolet (UV) radiation. Studies performed on mucosal HR HPV types, such as 16 and 18, showed that both oncoproteins E6 and E7 play a key role in cervical cancer by altering pathways involved in the host immune response to establish a persistent infection and by promoting cellular transformation. Continuous expression of E6 and E7 of mucosal HR HPV types is essential to initiate and to maintain the cellular transformation process, whereas expression of E6 and E7 of cutaneous HPV types is not required for the maintenance of the skin cancer phenotype. Beta HPV types appear to play a role in the initiation of skin carcinogenesis, by exacerbating the accumulation of UV radiation-induced DNA breaks and somatic mutations (the hit-and-run mechanism), and they would therefore act as facilitators rather than direct actors in NMSC. In this review, the natural history of HPV infection and the transforming properties of various HPV genera will be described, with a particular focus on describing the state of knowledge about the role of cutaneous HPV types in NMSC.

Interaction between susceptibility loci in cGAS-STING pathway, MHC gene and HPV infection on the risk of cervical precancerous lesions in Chinese population

Human papillomavirus (HPV) infection is a definite risk factor for cervical cancer. Nevertheless, only some infected individuals actually develop cervical cancer. The cGAS-STING pathway in innate immunity plays an important role in protecting against HPV infection. Chen et al. described that the rs2516448 SNP in the MHC locus may affect susceptibility to cervical cancer, a finding that we attempted to replicate in a Chinese population. To investigate the effects of cGAS, STING and MHC polymorphisms on susceptibility to cervical precancerous lesions, 9 SNPs were analyzed in 164 cervical precancerous lesion cases and 428 controls. Gene-gene and gene-environment interactions were also evaluated. We found a significantly decreased risk of cervical precancerous lesions for the GG genotype of rs311678 in the cGAS gene (ORadjusted = 0.40, 95% CI: 0.16-0.98). Moreover, MDR analysis identified a significant three-locus interaction model, involving HPV infection, age at menarche and rs311678 in cGAS. Additionally, a significant antagonistic interaction between HPV infection and rs311678 was found on an additive scale. In conclusion, our results indicate that the rs311678 polymorphism in the cGAS gene confers genetic susceptibility to cervical precancerous lesions. Moreover, the three-way gene-environment interactions further demonstrate that the rs311678 polymorphism in cGAS can significantly decrease the risk of HPV infection and the elder at menarche.

Defining the genetic susceptibility to cervical neoplasia-A genome-wide association study

A small percentage of women with cervical HPV infection progress to cervical neoplasia, and the risk factors determining progression are incompletely understood. We sought to define the genetic loci involved in cervical neoplasia and to assess its heritability using unbiased unrelated case/control statistical approaches. We demonstrated strong association of cervical neoplasia with risk and protective HLA haplotypes that are determined by the amino-acids carried at positions 13 and 71 in pocket 4 of HLA-DRB1 and position 156 in HLA-B. Furthermore, 36% (standard error 2.4%) of liability of HPV-associated cervical pre-cancer and cancer is determined by common genetic variants. Women in the highest 10% of genetic risk scores have approximately >7.1% risk, and those in the highest 5% have approximately >21.6% risk, of developing cervical neoplasia. Future studies should examine genetic risk prediction in assessing the risk of cervical neoplasia further, in combination with other screening methods.

Around 1% of women with cervical human papillomavirus (HPV) infection progress to cervical cancer. Previous studies had indicated that a person’s genetic makeup could predispose to HPV-associated cervical cancer, and that some of the genes likely to be involved include the immune-related human leukocyte antigen (HLA) genes among the major histocompatibility complex (MHC). However, it has been difficult to determine which alleles might be associated with cervical pre-cancer or cancer due to the complex and high level of co-inheritance of MHC alleles. Here, we performed a genome-wide association study that assessed the correlation of genetic variants among those with cervical cancer and healthy controls. We show that host genetics is a major determinant of HPV-associated cervical cancer, with 36% of liability due to common genetic variants in the population, and identify both risk and protective HLA alleles. Our study was also sufficiently powerful to identify particular residue variants on a number of the immune-related proteins that provide risk or protection, providing further insight into the biological basis for cervical cancer development. Our findings could lay the foundation for screening for people at increased risk of developing cancer following HPV infection, and aid in the treatment and prognosis of cervical cancer.

Association of single nucleotide polymorphisms in tumor necrosis factor-alpha with cervical cancer susceptibility

Tumor necrosis factor-alpha (TNF-α) polymorphisms have been reported to play an important role in the development of cervical cancer. But the results remain inconclusive. We performed this study to provide a comprehensive assessment of the association by means of a meta-analysis in which all published studies were included. The studies investigating the associations between cervical cancer risk and TNF-α polymorphisms were identified through PubMed, Embase, CNKI, and Chinese BioMedical Literature Database. OR and 95% CI (odds ratio and 95% confidence interval) were calculated using either the fixed or random effects model to assess the associations. We eventually included eighteen case-control studies of SNP -308 G>A and nine studies of SNP -238 G>A. Meta-analysis of the former polymorphism suggested significantly increased risk of cervical cancer associated with the A allele (OR 1.19, 95% CI 1.02-1.38). Subgroup analysis according to ethnicity showed similar results in Caucasians (A vs. G: OR 1.25, 95% CI 1.02-1.54; AA vs. GG: OR 1.47, 95% CI 1.04-2.08; AA vs. GA+GG: OR 1.47, 95% CI 1.04-2.08). For SNP -238 G>A, a protective association was observed in overall comparisons (A vs. G: OR 0.64, 95% CI 0.51-0.80; AA+GA vs. GG: OR 0.62, 95% CI 0.49-0.79) and subgroup analysis of Caucasians (A vs. G: OR 0.67, 95% CI 0.53-0.83; AA+GA vs. GG: OR 0.65, 95% CI 0.51-0.82). Our meta-analysis indicates that TNF-α polymorphisms may confer susceptibility to cervical cancer in an ethic-specific fashion.

Genetic susceptibility to cervical cancer: role of common polymorphisms in apoptosis-related genes

Cervical cancer is a common malignancy which poses a significant health burden among women, especially those living in the developing countries. Although human papillomavirus (HPV) infection has been unequivocally implicated in the etiopathogenesis of the cancer, it alone is not adequate to contribute to the malignant transformation of cervical cells. Most HPV infections regress spontaneously, and only a small proportion of women have persistent infections which eventually lead to malignancy. This suggests that interplays between HPV infection and other cofactors certainly exist during the process of cervical carcinogenesis, which synergistically contribute to the differential susceptibility of an individual to the malignancy. Undoubtedly, host genetic factors represent a major element involved in such a synergistic interaction, and accumulating evidence suggests that polymorphisms in apoptosis-related genes play an important role in the genetic susceptibility to cervical cancer. This review consolidates the recent literatures on the role of common polymorphisms in apoptosis-related genes in genetic susceptibility to cervical cancer.

IL-10 gene promoter and intron polymorphisms as genetic biomarkers of cervical cancer susceptibility among Tunisians

OBJECTIVE

We investigated the association between polymorphisms in the promoter and intron regions of the interleukin-10 (IL-10) gene with the risk of cervical cancer (CC) in Tunisian patients and control women.

METHODS

Study subjects comprised 86 CC cases and 126 control women. Genotyping of IL-10 intron (rs3024491, rs3024490) and promoter (rs1800872, rs1800871, rs1800896) variants was done by real-time PCR, with defined clusters.

RESULTS

The minor allele frequencies of the five tested IL-10 SNPs were not significantly different between cervical cancer cases and control women. However, significantly higher frequencies of homozygous minor allele-carriers in cases was seen for rs3024490 (P=0.023), rs1800872 (P=0.037), and rs1800871 (P=0.028). IL-10 serum levels were significantly reduced in rs3024490 T/T vs. G/G genotype carriers, and in rs1800871 T/T than C/C genotype carriers. While carriage of rs1800872 and rs3024491 minor allele was associated with reduced IL-10 secretion, this was not statistically significant. Haploview analysis demonstrated high linkage disequilibrium (LD) among the IL10 SNPs studied, and only seven haplotypes were common, capturing 98.8% of the total possible haplotypes. Reduced frequency of haplotypes GTCCA (P<0.001) and TGATG (P<0.001) was seen in cervical cancer cases than in control women, thus conferring disease protection nature to these haplotype. This association remained significant for GTCCA (Pc=0.006) and TGATG (P=0.045) after correcting for multiple comparisons.

CONCLUSION

Specific IL-10 variants (rs3024490, rs1800872, and rs1800871) and haplotype (GTCCA and TGATG) may contribute to the development of cervical cancer among Tunisian women.

Risk of malignancy associated with a maternal family history of cancer

This study was conducted in order to obtain a screening and early detection reference for children whose mothers had been diagnosed with cancer. Data for 276 mother-child pairs with malignant tumors were analyzed. The distribution of cancers in affected families was generally similar to that of the general Chinese population, and correspondingly breast cancer was the most common malignancy amongst daughters whose mother had cancer (32.7%). The most prevalent cancer amongst sons with affected mothers was gastric cancer, rather than lung cancer. Daughters were more likely to have the same kind of malignant tumor as their mother (P<0.05), and were more likely to develop breast cancer than any other malignant disease if their mother had a breast tumor (P<0.0001). Likewise, if the mother was diagnosed with breast or gynecological cancer, the daughter was more likely to be diagnosed with breast or gynecological cancer than any other cancer (P<0.01). Daughters and sons developed malignant diseases 11 and 6.5 years earlier than their mothers, respectively (P<0.0001).Women with a mother who suffered cancer should be screened for malignancy from 40 years of age especially for breast, lung, and gynecological cancers. For men with affected mothers, screening should start when they are 45 years old focusing particularly on lung and digestive system cancers.

Trends of cervical cancer in Greenland: a 60-year overview

BACKGROUND

Due to its extraordinarily fast economic and social transition, virtually closed borders before 1940 and, moreover, that 85% of the population has the distinctive genetics of the Inuit, Greenland is a very interesting country to study cervical cancer from a historical perspective. Nevertheless, little has been reported about long-term cancer trends in Greenland. Our aim was to describe and interpret the incidence of cervical cancer from 1950 to 2009.

MATERIAL AND METHODS

We systematically searched PubMed for articles reporting the incidence of cervical cancer in Greenland. We supplemented this with data for 1980-2009 obtained from the Chief Medical Officer of Greenland.

RESULTS

Incidence of cervical cancer was around 10 per 100 000 women (age-standardised, world population, ASW) in the 1950s, 30 per 100 000 in the 1960s, and in the 1980s around 60 per 100 000. From 1985 onwards, the incidence of cervical cancer started decreasing to the current level of 25 per 100 000.

CONCLUSION

The steep increase in the incidence of cervical cancer from the 1950s onwards is unlikely to be explained by increasing completeness of data. In parallel with the economic development, however, out-of-wedlock births (proxy for sexual behaviour) increased dramatically from 1935 onwards while tobacco use increased from the 1950s onwards. From the late 1960s to around 1990, data suggested rather stable but high levels of sexual habits. The decrease in the incidence of cervical cancer since 1985 is consistent with the introduction of screening. The data strongly suggested that the increased burden of cervical cancer in Greenlandic women was real and followed earlier changes in sexual behaviour; these changes were likely a consequence of the tremendous societal changes.

Association between MTHFR C677T, MTHFR A1298C and MS A2756G polymorphisms and risk of cervical intraepithelial neoplasia II/III and cervical cancer: a meta-analysis

Numerous case-control studies on the association between polymorphisms of key genes involved in methionine remethylation [methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS)] and the susceptibility of cervical intraepithelial neoplasia (CIN) and cervical cancer have provided inconclusive results. The aim of the present meta-analysis was to determine the effects of two MTHFR (C677T and A1298C) and one MS gene polymorphism (A2756G) on the risk of CIN II/III or cervical cancer. Relevant data were retrieved following a systematic search in PubMed, Web of Science, MEDLINE and Wanfang Data up to November 2012. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated from eligible studies by meta-analysis with subgroup analyses stratified by ethnicity. A total of 13 studies with 1,936 cases and 2,858 controls were included in the present meta‑analysis. An increased risk of cervical cancer was found in Asian women with the MTHFR 677T allele (TT vs. CC: OR=1.41, 95% CI=1.07‑1.86, P=0.01; TT vs. CC+CT: OR=1.38, 95% CI=1.08-1.75, P=0.008), while a decreased risk was observed in Caucasian women (TT vs. CC: OR=0.65, 95% CI=0.45-0.93, P=0.02; TT+CT vs. CC: OR=0.7, 95% CI=0.58-0.86, P=0.0005). No effects of MTHFR C677T polymorphism on CIN II/III risk and MTHFR A1298C or MS A2756G polymorphisms on cervical cancer risk were detected. The sensitivity analysis suggested stability of this meta-analysis and no publication bias was detected. The MTHFR 677T allele may enhance the risk of cervical cancer in the Asian female population and play a protective role in Caucasian females. However, limited association is suggested between MTHFR A1298C and MS A2756G polymorphisms with cervical tumorigenesis.

RPS19 and TYMS SNPs and Prevalent High Risk Human Papilloma Virus Infection in Nigerian Women

High risk HPV (hrHPV) infection is a necessary cause of cervical cancer but the host genetic determinants of infection are poorly understood. We enrolled 267 women who presented to our cervical cancer screening program in Abuja, Nigeria between April 2012 and August 2012. We collected information on demographic characteristics, risk factors of cervical cancer and obtained samples of blood and cervical exfoliated cells from all participants. We used Roche Linear Array HPV Genotyping Test® to characterize the prevalent HPV according to manufacturer's instruction; Sequenom Mass Array to test 21 SNPs in genes/regions previously associated with hrHPV and regression models to examine independent factors associated with HPV infection. We considered a p<0.05 as significant because this is a replication study. There were 65 women with and 202 women without hrHPV infection. Under the allelic model, we found significant association between two SNPs, rs2305809 on RPS19 and rs2342700 on TYMS, and prevalent hrHPV infection. Multivariate analysis of hrHPV risk adjusted for age, body mass index, smoking, age of menarche, age at sexual debut, lifetime total number of sexual partners and the total number of pregnancies as covariates, yielded a p-value of 0.071 and 0.010 for rs2305809 and rs2342700, respectively. Our findings in this unique population suggest that a number of genetic risk variants for hrHPV are shared with other population groups. Definitive studies with larger sample sizes and using genome wide approaches are needed to understand the genetic architecture of hrHPV risk in multiple populations.

Pharmacogenomics of Viral Diseases

Viral diseases are leading cause of deaths worldwide as WHO report suggests that hepatitis A virus (HAV) infects more than 80 % of the population of many developing countries. Viral hepatitis B (HBV) affects an estimated 360 million people, whereas hepatitis C affects 123 million people worldwide, and last but not least, at current, India has an HIV/AIDS population of approximately 2.4 million people and more than 30 million in whole world and now it has become a reason for 1.8 million death globally; thus, millions of people still struggle for their lives.

The progress in medical science has made it possible in overcoming the various fatal diseases such as small pox, chicken pox, dengue, etc., but human immunodeficiency viruses, influenza, and hepatitis virus have renewed challenge surprisingly. The obstacles and challenges in therapy include existence of antibiotic resistance strains of common organisms due to overuse of antibiotics, lack of vaccines, adverse drug reaction, and last but not least the susceptibility concerns. Emergence of pharmacogenomics and pharmacogenetics has shown some promises to take challenges. The discovery of human genome project has opened new vistas to understand the behaviors of genetic makeup in development and progression of diseases and treatment in various viral diseases. Current and previous decade have been engaged in making repositories of polymorphisms (SNPs) of various genes including drug-metabolizing enzymes, receptors, inflammatory cells related with immunity, and antigen-presenting cells, along with the prediction of risks. The genetic makeup alone is most likely an adequate way to handle the therapeutic decision-making process for previous regimen failure. With the introduction of new antiviral therapeutic agents, a significant improvement in progression and overall survival has been achieved, but these drugs have shown several adverse responses in some individuals, so the success is not up to the expectations. Research and acquisition of new knowledge of pharmacogenomics may help in overcoming the prevailing burden of viral diseases. So it will definitely help in selecting the most effective therapeutic agents, effective doses, and drug response for the individuals. Thus, it will be able to transform the laboratory research into the clinical bench side and will also help in understanding the pathogenesis of viral diseases with drug action, so the patients will be managed more properly and finally become able to fulfill the promise of the future.

A comprehensive review on host genetic susceptibility to human papillomavirus infection and progression to cervical cancer

Cervical cancer is the second most common cancer in women worldwide. This is caused by oncogenic types of human papillomavirus (HPV) infection. Although large numbers of young sexually active women get HPV-infected, only a small fraction develop cervical cancer. This points to different co-factors for regression of HPV infection or progression to cervical cancer. Host genetic factors play an important role in the outcome of such complex or multifactor diseases such as cervical cancer and are also known to regulate the rate of disease progression. The aim of this review is to compile the advances in the field of host genetics of cervical cancer. MEDLINE database was searched using the terms, ‘HPV’, ‘cervical’, ‘CIN’, ‘polymorphism(s)’, ‘cervical’+ *the name of the gene* and ‘HPV’+ *the name of the gene*. This review focuses on the major host genes reported to affect the progression to cervical cancer in HPV infected individuals.

Single nucleotide polymorphisms in the PRDX3 and RPS19 and risk of HPV persistence and cervical precancer/cancer

Background

Host genetic factors might affect the risk of progression from infection with carcinogenic human papillomavirus (HPV), the etiologic agent for cervical cancer, to persistent HPV infection, and hence to cervical precancer and cancer.

Methodology/Principal Findings

We assessed 18,310 tag single nucleotide polymorphisms (SNPs) from 1113 genes in 416 cervical intraepithelial neoplasia 3 (CIN3)/cancer cases, 356 women with persistent carcinogenic HPV infection (median persistence of 25 months) and 425 randomly selected women (non-cases and non-HPV persistent) from the 10,049 women from the Guanacaste, Costa Rica HPV natural history cohort. For gene and SNP associations, we computed age-adjusted odds ratio and p-trend. Three comparisons were made: 1) association with CIN3/cancer (compared CIN3/cancer cases to random controls), 2) association with persistence (compared HPV persistence to random controls), and 3) progression (compared CIN3/cancers with HPV-persistent group). Regions statistically significantly associated with CIN3/cancer included genes for peroxiredoxin 3 PRDX3, and ribosomal protein S19 RPS19. The single most significant SNPs from each gene associated with CIN3/cancer were PRDX3 rs7082598 (P_trend<0.0001), and RPS19 rs2305809 (P_trend=0.0007), respectively. Both SNPs were also associated with progression.

Conclusions/Significance

These data suggest involvement of two genes, RSP19 and PRDX3, or other SNPs in linkage disequilibrium, with cervical cancer risk. Further investigation showed that they may be involved in both the persistence and progression transition stages. Our results require replication but, if true, suggest a role for ribosomal dysfunction, mitochondrial processes, and/or oxidative stress, or other unknown function of these genes in cervical carcinogenesis.

Null genotypes of GSTM1 and GSTT1 contribute to risk of cervical neoplasia: an evidence-based meta-analysis

Background and Objectives

Glutathione S-transferases (GSTs) are multifunctional enzymes that play a key role in the detoxification of varieties of both endogenous products of oxidative stress and exogenous carcinogens.

Methods

In this meta-analysis, twenty-five studies were identified by searching PubMed, EMBASE, ISI Web of Science and CBM databases: 23 evaluated GSTM1 and 19 evaluated GSTT1. Crude odds ratios with corresponding 95% confidence intervals were used to estimate the association between GSTM1 and GSTT1 polymorphisms and risk of cervical neoplasia. Subgroup analyses were conducted by pathological history, ethnicity, source of DNA for genotyping, quality score, and matching variable.

Results

The null genotypes of GSTM1 and GSTT1 polymorphisms were associated with a significantly increased risk of cervical neoplasia (for GSTM1: OR = 1.40; 95%CI, 1.19–1.65; for GSTT1: OR = 1.30; 95%CI, 1.05–1.62, respectively). Subgroup analyses showed that the null genotype of GSTM1 increased the risk of cervical neoplasia in Asians, studies with DNA isolation from white blood cells and tissue samples, both high and low quality studies, and matched studies. In GSTM1-GSTT1 interaction analysis, individuals with dual null genotype were associated with a significantly increased risk of cervical neoplasia (OR = 1.72; 95%CI, 1.18–2.51).

Conclusion

These findings indicate that GSTM1 and GSTT1 polymorphisms, particularly GSTM1-GSTT1 interaction, may play critical roles in the development of cervical neoplasia. A conservative manner should be adopted to interpret these results because of obvious heterogeneity between-study, unadjusted data, and relatively small sample size in this meta-analysis. Well designed studies with larger sample size are of great value to confirm these results.

Folate and choline metabolism gene variants and development of uterine cervical carcinoma

OBJECTIVE

It has been reported that aberrant DNA methylation can be associated with HPV infection and cervical tumorigenesis. The aim of this study was to evaluate the possibility that polymorphic variants of genes that may affect DNA methylation status are associated with the risk of cervical cancer in the Polish population.

DESIGN AND METHOD

Employing PCR-RFLPs and HRM analyses, we examined the prevalence of BHMT Arg239Gln (rs3733890), MTR Asp919Gly (rs1805087), MTHFR Ala222Val (rs1801133), MTHFD1 Arg653Gln (rs2236225) and MTRR Ile22Met (rs1801394) genotypes and alleles in patients with advanced cervical cancer (n=124) and controls (n=168).

RESULTS

The odds ratio (OR) for BHMT Gln/Gln genotype was 0.433 (95% CI=0.1780-1.054; p=0.0602). The OR for patients having the BHMT Arg/Gln or Gln/Gln genotypes was 0.579 (95% CI=0.3622-0.924; p=0.0216). We also observed a significantly higher frequency of the BHMT 239Gln allele in controls than in patients, p=0.0165. The genotype and allele frequencies of the MTR Asp919Gly, MTHFR Ala222Val, MTHFD1 Arg653Gln and MTRR Ile22Met gene variants did not display statistical differences between patients with cervical cancer and controls. We also did not find a significant association between the distribution of any genotypes or alleles and cancer characteristics.

CONCLUSION

Our results might suggest the protective role of the BHMT 239Gln variant in cervical cancer incidence.

Distribution of CCND1 A870G polymorphism in patients with advanced uterine cervical carcinoma

We examined the distribution of the CCND1 A870G (rs9344) polymorphic variant in patients with cervical cancer (n = 129) and healthy individuals (n = 288) in a sample of a Polish cohort. We showed that patients with advanced cervical cancer bearing the CCND1 A/A and A/G genotypes displayed a 1.811-fold increased risk of cervical cancer (95% CI = 1.150-2.852, p = 0.0098). We also found a significantly higher frequency of the CCND1 870A allele in patients with cancer than in controls, p = 0.0116. Our investigation confirmed that the CCND1 870A gene variant may be a genetic risk factor in the incidence of advanced cervical cancer.

CCR2-V64I polymorphism is associated with increased risk of cervical cancer but not with HPV infection or pre-cancerous lesions in African women

BACKGROUND

Cervical cancer, caused by specific oncogenic types of human papillomavirus (HPV), is the second most common cancer in women worldwide. A large number of young sexually active women get infected by HPV but only a small fraction of them have persistent infection and develop cervical cancer pointing to co- factors including host genetics that might play a role in outcome of the HPV infection. This study investigated the role of CCR2-V64I polymorphism in cervical cancer, pre-cancers and HPV infection in South African women resident in Western Cape. CCR2-V64I polymorphism has been previously reported to influence the progression to cervical cancer in some populations and has also been associated with decreased progression from HIV infection to AIDS.

METHODS

Genotyping for CCR2-V64I was done by PCR-SSP in a case-control study of 446 women (106 black African and 340 mixed-ancestry) with histologically confirmed invasive cervical cancer and 1432 controls (322 black African and 1110 mixed-ancestry) group-matched (1:3) by age, ethnicity and domicile status. In the control women HPV was detected using the Digene Hybrid Capture II test and cervical disease was detected by cervical cytology.

RESULTS

The CCR2-64I variant was significantly associated with cervical cancer when cases were compared to the control group (P = 0.001). Further analysis comparing selected groups within the controls showed that individuals with abnormal cytology and high grade squamous intraepitleial neoplasia (HSIL) did not have this association when compared to women with normal cytology. HPV infection also showed no association with CCR2-64I variant. Comparing SIL positive controls with the cases showed a significant association of CCR2-64I variant (P = 0.001) with cervical cancer.

CONCLUSIONS

This is the first study of the role of CCR2-V64I polymorphism in cervical cancer in an African population. Our results show that CCR2-64I variant is associated with the risk of cervical cancer but does not affect the susceptibility to HPV infection or HSIL in South African women of black and mixed-ancestry origin. This result implies that the role of CCR2 is important in invasive cancer of the cervix but not in HPV infection or in the development of pre-cancers.

Fas and FasL gene polymorphisms are not associated with cervical cancer but differ among Black and Mixed-ancestry South Africans

Background

Cervical cancer is one of the most important cancers in African women. Polymorphisms in the Fas (FasR) and Fas ligand (FasL) genes have been reported to be associated with cervical cancer in certain populations. This study investigated whether these polymorphisms are associated with cervical cancer or human papillomavirus (HPV) infection in South African women.

Findings

Participants were 447 women with invasive cervical cancer (106 black African and 341 women of mixed-ancestry) and 424 healthy women controls, matched by age, (101 black African and 323 women of mixed-ancestry) and domicile (rural or urban). Two polymorphisms in Fas gene (FasR-1377G/A, FasR-670A/G) and one in FasL gene (FasL844T/C) were genotyped by TaqMan. None of the polymorphisms, or the Fas haplotypes, showed a significant association with cervical cancer. There was also no association with HPV infection in the control group. However, on analysis of the control group, highly significant allele, genotype and haplotype differences were found between the two ethnic groups. There were generally low frequencies of FasR-1377A alleles, FasR-670A alleles and FasL-844C alleles in black women compared to the women of mixed-ancestry.

Conclusion

This is the first study on the role of Fas and FasL polymorphisms in cervical cancer in African populations. Our results suggest that these SNPs are not associated with cervical cancer in these populations. The allele frequencies of the three SNPs differed markedly between the indigenous African black and mixed-ancestry populations.

Association of HLA-DRB1, interleukin-6 and cyclin D1 polymorphisms with cervical cancer in the Swedish population--a candidate gene approach

High-risk human papillomavirus (hrHPV) infection is the major risk factor for cervical cancer (CxCa). The role of genetic susceptibility in the disease has been suggested, but the existing data lack consistency. We conducted a nested case-control study on 973 CxCa cases and 1,763 matched controls, from two Swedish population-based cohorts to examine the association of common genetic variants with CxCa risk. Human leukocyte antigen (HLA) alleles and 24 other polymorphisms in 14 genes were selected on the basis of reported association or mechanistic plausibility with an HPV infection or cervical cancer development. Genotyping was conducted using multiplex PCR and Luminex technology. A significant association of CxCa with various polymorphisms was observed: rs1800797 in the IL-6 gene (odds ratio [OR] = 0.88, 95% confidence intervals [CI]: 0.79-0.99); rs1041981 in the LTA gene (OR = 0.87, 95% CI: 0.78-0.98), and rs9344 in the CCND1 gene (OR = 1.14, 95% CI: 1.02-1.27), for those individuals carrying the rare allele. Additionally, the alleles 0401 and 1501 of the HLA class II DRB1 locus were associated with an increased risk (OR = 1.23, 95% CI: 1.04-1.45 and OR = 1.29, 95% CI: 1.11-1.50, respectively), and allele 1301 was associated with decreased risk (OR = 0.59, 95% CI: 0.47-0.73). The effects of CCND1 and the HLA*DRB1 alleles were independent of the effect of smoking. We did not find any association of risk with polymorphisms in genes related to the innate immune system. In conclusion, our study provides evidence for genetic susceptibility to CxCa due to variations in genes involved in the immune system and in cell cycle.

Impact of x chromosome genes in explaining the excess risk of cancer in males

The authors examined cancer incidence sex ratios in Denmark for 1943-2003 by age group. At nongenital/nonbreast sites, incidences were consistently higher in males. While environmental factors dominate cancer risk, the authors hypothesized that the higher risk in males might be explained by unspecified X chromosome genes' protecting female cells from genotoxic damage. If so, cancer susceptibility would be passed from parent to offspring differently by sex. The authors compared relative risks in offspring of parents with and without cancer histories. For all comparisons, relative risks were similar in offspring of fathers with cancer (relative risk (RR) = 1.14, 95% confidence interval: 1.08, 1.20). Risks in offspring were higher for parents diagnosed before age 50 years and for cancers at the same site rather than different sites. Genital cancer risks were increased in same-sex offspring of parents with genital cancers. Breast cancer risks were high in both daughters (RR = 2.37) and sons (RR = 4.63) of mothers with breast cancer and in daughters (RR = 5.96) of fathers with breast cancer. Thus, X chromosome genetic factors were not responsible for the excess risk of cancer in males. Susceptibility to genital cancer was increased in same-sex offspring, and breast cancer risks were increased in both sons and daughters when either parent had had breast cancer.

Family history of cancer predicts Papanicolaou screening behavior for African American and white women

BACKGROUND

Understanding women's motivations for getting Papanicolaou (Pap) screening has the potential to impact cancer disparities. This study examined whether having a family history of cancer was a predictor for Pap screening.

METHODS

By using the National Health Interview Survey 2000 Cancer Control and Family modules, we identified a subsample (n=15,509) of African American (n=2774) and white women (n=12,735) unaffected by cancer, with and without a family history of cancer. Data were analyzed using logistic regression models.

RESULTS

African American and white women with a positive family history of cancer were 42% (P<.0001) more likely to have had a recent Papanicolaou (Pap) test than their counterparts without a family history of cancer. Among African American women, those with a positive family history of cancer were 53% more likely to have had a recent Pap test, whereas among white women those with a positive family history of cancer were 41% more likely to have received a Pap test. African American women with a family history of cancer were more likely to have had a recent Pap test than white women with or without a family history of cancer.

CONCLUSIONS

This study presents a unique perspective on Pap screening behavior. Having an immediate family member with any cancer statistically predicted having a recent Pap test for both African American and white women. Because these results demonstrated that regardless of the cancer type, having an immediate affected family member is a motivator for cervical cancer screening behavior, healthcare providers managing cancer treatment patients have a teachable opportunity that extends beyond the patient.

Familial risks for cervical tumors in full and half siblings: etiologic apportioning

Many studies have shown familial aggregation for cervical cancer, but they have been unable to distinguish between shared environmental and genetic effects. Full and half-siblings were identified from the nationwide Swedish Family-Cancer Database, including invasive and in situ cervical cancers in women up to age 70 years. Half-siblings were defined through a common father or mother. Standardized incidence ratios, adjusted for several variables, were calculated for proband-wise risks between full and half-siblings. The familial risk for full siblings was 1.84, compared with 1.40 for maternal and 1.27 for paternal half-siblings. These data were used to apportion familial risk for cervical tumors in full siblings into a heritable component, accounting for 64%, and an environmental component, accounting for 36% of the total risk. No evidence for gene-environment interactions was found. The intractable difficulty in separating cervical cancer causation will be an obstacle for a successful identification of susceptibility genes.

Reduced incidence of cervical cancer in mothers of sons with allergic rhinoconjunctivitis, asthma or eczema

Because infection with human papillomavirus is a necessary cause of cervical cancer, it is likely that host immunological factors involved in defense against such infections are important for susceptibility to this cancer. By examining associations between allergy in sons and cervical cancer in their mothers, we aimed to test for genetic components involved in both allergy and cervical cancer development. Women born in Sweden between 1932 and 1960 with at least 1 son with medical records from military conscription examination were included in the study (N = 717,963). Among these women there were 41,910 in situ and 3,618 invasive cases of cervical cancer. Hazard ratios of in situ and invasive cervical cancer were estimated as functions of allergic rhinoconjunctivitis, asthma and eczema diagnoses in sons. Adjustment was made for the possible confounders: age, year of birth, education, socio-economic index, geography, number of conscripted sons and total number of offspring. The risk of in situ and invasive cervical cancer was lower for women having sons diagnosed with hypersensitivity (allergic rhinoconjunctivitis, asthma or eczema). Fully adjusted hazard ratios for women with 1 hypersensitive son were for in situ 0.86 (95% CI 0.84-0.88) and for invasive cervical cancer 0.82 (95% CI 0.74-0.91). The protective effects were similar between the 3 allergic diagnoses and increased with number of sons with a diagnosis. There was no significant association between non-cervical cancer in mothers and allergy in sons. These results strengthen the hypothesis that inherited immunological factors are important in determining risk of cervical cancer, probably by affecting mechanisms for viral persistence.

Chapter 28: Studies to assess the long-term efficacy and effectiveness of HPV vaccination in developed and developing countries

We review studies of the implementation of human papillomavirus (HPV) vaccination programmes in developed and developing countries. The review spans the period from establishment of long-term vaccine efficacy follow-up studies, operational research on issues of vaccine preparedness, and relevant predictive modelling studies during the pre-licensure phase to plans of phase IV effectiveness trials, forms of epidemiological surveillance, and further operational research in the post-licensure phase. Much of the research is already ongoing. Depending on the results of the planned immuno bridging studies among HIV-negative and HIV-positive women, further phase III and/or phase IV trials may be warranted.

Vaccines for cervical cancer

The review focuses on current and future prevention of invasive cervical cancer (ICC), the second most common cancer among women worldwide. Implementation of population-based cytological screening programmes, using the 'Pap' smear to detect pre-cancerous lesions in the cervix, has resulted in substantial declines in mortality and morbidity from ICC in North America and some European countries. However, cases of, and deaths from, ICC continue to occur. Primary prevention of infection with high-risk human papillomavirus (HPV) types, the central causal factor of ICC, could further reduce incidence of and mortality from ICC. This is particularly the case in developing countries, which bear 80% of the burden of ICC, and where effective Pap screening programmes are extremely difficult to implement. Very promising results from several trials of synthetic HPV type-specific monovalent (HPV 16) and bivalent (HPV 16 and 18) vaccines have recently been published, showing high efficacy against type-specific persistent HPV infection and development of type-specific pre-cancerous lesions. Large-scale phase III trials of a number of such vaccine candidates are currently underway, and there is real hope that an effective vaccine capable of protecting against infection with HPV types 16 and 18 (which together account for approximately 70% of cervical cancer cases worldwide), and thereby of preventing development of a very significant proportion of cases of ICC, could be available within the next 2 years.

Heritable and environmental components in cervical tumors

The familial risk of 18,199 women with invasive and/or in situ cervix cancers when compared with that of 72,796 women free of cervical tumors was analyzed. The risk of cervical tumors was significantly higher for women with a mother and/or sister(s) with cervical tumors (odds ratio (OR) = 1.79, 95% CI: 1.71-1.88) than with an affected grandmother and/or aunt(s) (OR = 1.28, 1.22-1.35). This risk did not differ according to the family side of the affected relative. Taking the familial risk of 1.28 for second-degree relatives as the best estimate of a true heritable effect for 25% of gene sharing, the calculated heritable effect for full siblings, sharing 50% of their genes, would correspond to an OR of 1.56. This model suggests, as a best estimate, a heritable component of 71% and an environmental component of 29% in young familial cervical tumors. The data imply that familial risks for cervical tumors are best explained by complex multifactorial mechanisms.

Cyclin D1 G870A polymorphism and squamous cell carcinoma of the uterine cervix in Korean women

Though many investigators have reported relationships between the CCND1 polymorphism and susceptibility to various carcinomas, to our knowledge, no report has been issued concerning its relationship with uterine cervical cancer. Thus, we undertook this study to investigate the association between CCND1 polymorphisms and susceptibility to cervical cancer in Korean women. This study was carried on 222 patients with squamous cell carcinoma of uterine cervix and on 314 normal controls. CCND1 genotyping was determined by polymerase chain reaction and restriction fragment length polymorphism. The allelic frequencies of the cases (A, 0.53; G, 0.47) were not significantly different from those of the controls (A, 0.49; G, 0.51) (P=0.238). Regression analysis after adjusting for age showed that the CCND1 G870A genotypes are not related to the risk of squamous cell carcinoma of the uterine cervix. Our findings suggest that the CCND1 polymorphism is not associated with an increased risk of squamous cell carcinoma of uterine cervix in Korean women.

Clinical genetic counselling for familial cancers requires reliable data on familial cancer risks and general action plans

Familial cancer clustering, without obvious heritability, poses a major challenge for current cancer risk assessment and management. Reliable determination of familial risks for cancer is important for clinical genetic counselling, but medically verified data on familial risks for many malignancies have been limited. However, the nationwide Swedish Family-Cancer Database allows a reliable characterisation of familial risk for all major neoplasms. Even though alert genetic counsellors and certainly clinical cancer geneticists will consider familial cancer clustering in their purview, the standard medical referral systems, which have already been shown to be poor in capturing and referring families at high risk for heritable cancers, are unlikely to ascertain familial aggregations of other cancers that are not known to belong to an inherited cancer syndrome. The data will be helpful in implementing evidence based guidelines for helping the general medical system to ascertain and refer even familial cancer clusters to cancer genetics professionals.

Single nucleotide polymorphisms (SNPs) are inherited from parents and they measure heritable events

Single nucleotide polymorphisms (SNPs) are extensively used in case-control studies of practically all cancer types. They are used for the identification of inherited cancer susceptibility genes and those that may interact with environmental factors. However, being genetic markers, they are applicable only on heritable conditions, which is often a neglected fact. Based on the data in the nationwide Swedish Family-Cancer Database, we review familial risks for all main cancers and discuss the evidence for a heritable component in cancer. The available evidence is not conclusive but it is consistent in pointing to a minor heritable etiology in cancer, which will hamper the success of SNP-based association studies. Empirical familial risks should be used as guidance for the planning of SNP studies. We provide calculations for the assessment of familial risks for assumed allele frequencies and gene effects (odds ratios) for different modes of inheritance. Based on these data, we discuss the gene effects that could account for the unexplained proportion of familial breast and lung cancer. As a conclusion, we are concerned about the indiscriminate use of a genetic tool to cancers, which are mainly environmental in origin. We consider the likelihood of a successful application of SNPs in gene-environment studies small, unless established environmental risk factors are tested on proven candidate genes.

Familial association of colorectal adenocarcinoma with cancers at other sites

Data on the familial associations of colorectal cancer (CRC) of adenocarcinoma histology are limited, but they are of interest because they may give us clues about as yet unknown family clusters. We calculated standardised incidence ratios (SIRs) for right- and left-sided colon cancer and rectal cancer in offspring using data from the Swedish Family-Cancer Database covering familial tumours from 1991 to 2000. The offspring were at an increased risk of developing colon adenocarcinoma when parents presented with CRC (SIR 1.81), endometrial (SIR 1.52) and kidney (SIR 1.42) cancers. The SIRs in siblings were increased when a co-sibling was diagnosed with CRC (SIR 3.26), myeloma (SIR 2.65) and leukaemia (SIR 2.53). Right-sided colon cancer was associated with familial pancreatic, squamous cell skin cancers, thyroid gland cancer and Hodgkin's disease. Left-sided colon cancer was associated with testicular cancers. Rectal cancer was associated with cervical and genital cancers in mothers. Most of the findings were consistent with data on known cancer syndromes. A new association was noted where rectal cancer in offspring was related to cervical and female genital cancers in mothers through an unknown mechanism. Hodgkin's disease and myeloma were also associated with right-sided colon cancer in offspring. The association with carcinoma of the testis, renal parenchyma, skin and leukaemia need to be confirmed in an independent series.

Familial cervical cancer: case reports, review and clinical implications

We report three Dutch families with familial clustering of (pre)neoplastic cervical disease, review the literature on familial risks of cervical intraepithelial neoplasia (CIN) and cervical cancer, and discuss possible practical guidelines for women with a family history of cervical cancer. Daughters and sisters of women with cervical cancer have been reported to have a relative risk of 1.5-2.3 to develop this type of cancer. From a practical clinical point of view, we suggest that as in women with an increased non-genetic risk to develop cervical cancer (e.g. because of immunosuppressive therapy) increased surveillance to detect this tumour should be considered in women with an increased risk based on family history. Cessation of smoking should be advised. As the use of condoms at least prevents HPV re-infection its use can be recommended as a way to lower the cervical cancer risk. Future studies to determine the genetic contribution to the development of cervical cancer should include the paternal family history of cancer and, because genetic predisposition might express itself as a higher risk to develop precursors of cervical cancer, carcinoma in situ and CIN grade II-III.

Association of brain tumours with other neoplasms in families

We used the nationwide Swedish Family-Cancer Database to analyse the association of histology-specific brain tumours with other cancers in family members. Among 0-68-year-old offspring, 9414 patients with brain tumours were identified from 1961 to 2000, of whom, 3387 parents were diagnosed with any primary neoplasm. Astrocytoma, meningioma and neurinoma were the main histological types. Increased standardised incidence ratios (SIRs) were found for brain tumours in association with cancers at sites that are known features in recognised syndromes, such as haemangioblastoma and renal cancer in von Hippel-Lindau disease. In addition, an association between astrocytoma and melanoma was recognised. Among as yet unknown clustering, neurinoma was associated with testicular cancer and myeloma; meningioma was associated with cervical cancer; astrocytoma was associated with prostate cancer; ependymoma was associated with breast cancer. Although some of these may feature a true tumour cluster, they need to be confirmed in another setting.

Genetic epidemiology of cancer: From families to heritable genes

A reliable determination of familial risks for cancer is important for clinical counseling, prevention and understanding cancer etiology. Family-based gene identification efforts may be targeted if the risks are well characterized and the mode of inheritance is identified. Medically verified data on familial risks have not been available for all types of cancer but they have become available through the use of the nationwide Swedish Family-Cancer Database, which includes all Swedes born in 1932 and later with their parents, totaling over 10 million individuals. Over 150 publications have emanated from this source. The familial risks of cancer have been characterized for all main cancers and the contribution of environmental and heritable effects to the familial aggregation has been assessed. Furthermore, the mode of inheritance has been deduced by comparing risks from parental and sibling probands. Examples are shown on familial clustering of cancers, for which heritable susceptibility genes are yet unknown, such as squamous cell carcinoma of the skin, intestinal carcinoids, thyroid papillary tumors, brain astrocytomas and pituitary adenomas. Some common cancers, such as lung and kidney cancers, appear to show an early-onset recessive component because familial risks among siblings are much higher than those in families where parents are probands. Many of the cancer sites showing high familial risks lack guidelines for clinical counseling or action level. In conclusion, we recommend that any future gene identification efforts, either using linkage or association designs, devise their strategies based on data from family studies. Clinical genetic counseling would benefit from reviewing established familial risks on all main types of cancer.

X chromosome inactivation in cervical cancer patients

Development of cervical carcinomas is strongly associated with presence of human papilloma virus (HPV). Recently we found that young patients with breast cancer had a higher frequency of skewed X inactivation in peripheral blood cells, indicating an effect of X-linked genes on breast cancer development. In this study, we investigated the frequency of skewed X-inactivation pattern in blood and tumor biopsies from patients with cervical cancer. No difference in the frequency of skewed X inactivation in blood was found between 142 patients and 437 age-matched controls. Elderly females have a higher frequency of skewed X inactivation in blood cells than younger females. An age effect was confirmed in this study for blood cells in both patients and controls. A tendency to an age effect was also found in the tumor biopsies. The correlation between X inactivation in blood and biopsies was 0.39 (P<0.001), showing that the X inactivation in biopsies to some degree reflects skewing in blood. Furthermore, of eight patients with a skewing of > or =75% in biopsies, seven patients had a skewing in the same direction in their blood cells (P=0.03). Our results indicate that if X-inactivation analysis is to be used in clonality studies of cervical cancers, it is essential to consider both the age and the X-inactivation pattern in blood cells.

Familial invasive and in situ squamous cell carcinoma of the skin

We used the updated nation-wide Swedish Family-Cancer Database to examine familial risks in data from 1961 to 1998 on 1252 invasive and 2474 in situ squamous cell carcinoma (SCC) of the skin among offspring, and over 10 times more among parents. In 259 families a parent and an offspring had skin SCC. The familial standardised incidence ratios (SIRs) were 2.72 for invasive and 2.40 for in situ skin cancers in offspring. Multiple skin cancers in parents were associated with increased SIRs for invasive SCC in offspring, being 2.55 for one and up to 14.93 for two invasive and two in situ cancers in parents; the corresponding in situ SCC risks were 2.28 and 7.49. The population attributable fraction for any familial skin SCC, invasive or in situ, was 4.1%. Melanoma was the only discordant tumour that was associated with invasive and in situ skin SCC. These results provide evidence that there is an underlying hereditary susceptibility for at least a part of the familial clustering for skin SCC.

Familial risk of cancer: Data for clinical counseling and cancer genetics

Familial risks for cancer are important for clinical counseling and understanding cancer etiology. Medically verified data on familial risks have not been available for all types of cancer. The nationwide Swedish Family-Cancer Database includes all Swedes born in 1932 and later (0-to 68-year-old offspring) with their parents, totaling over 10.2 million individuals. Cancer cases were retrieved from the Swedish Cancer Registry up to year 2000. Standardized incidence ratios (SIR) and 95% confidence limits (CI) were calculated for age-specific familial risk in offspring by an exact proband status. The familial risks for offspring cancer were increased at 24/25 sites from concordant cancer in only the parent, at 20/21 sites from a sibling proband and at 12/12 sites from a parent and sibling proband. The highest SIRs by parent were for Hodgkin's disease (4.88) and testicular (4.26), non-medullary thyroid (3.26), ovarian (3.15) and esophageal (3.14) cancer and for multiple myeloma (3.33). When a sibling was affected, even prostate, renal, squamous cell skin, endocrine, gastric and lung cancer and leukemia showed SIRs in excess of 3.00. The highest cumulative risks were found for familial breast (5.5%) and prostate (4.2%) cancers. We identified reliable familial risks for 24 common neoplasms, most of which lack guidelines for clinical counseling or action level. If, for example, a familial SIR of 2.2 would be use as an action level, counseling would be needed for most cancers at some diagnostic age groups. The present data provide the basis for clinical counseling.

Familial risk of cancer by site and histopathology

Familial risks for histopathology-specific cancers have not been determined. We used the nationwide Swedish Family-Cancer Database on 10.2 million individuals and 1 million tumors to calculate standardized incidence ratios (SIRs) for familial cancers of specific histology and morphology among 0- to 66-year-old offspring. We used histology codes for both offspring and parents, but because of the limited number of cases, the morphology-specific classification could be used only for offspring by all site-specific cancers in parents, resulting in inflated risk estimates. A number of novel findings emerged in the histopathology-specific analysis of familial risks, in addition to some known associations. Overall, specific histology showed an SIR of 2.07 for all cancers compared to an SIR of 2.00 for any histology. However, the small effect was due to breast and prostate cancers, which showed a negligible effect of specific histology. Familial risks of over 4.0 were found for serous papillary cystadenocarcinoma of the ovary, papillary thyroid cancer and low-grade astrocytoma. Familial risks of over 3.0 were found for signet-ring gastric cancer, various forms of ovarian cancer and squamous cell skin cancer. Also noteworthy were familial risks of hepatocellular carcinoma (2.48), pancreatic adenocarcinoma (1.92), large cell carcinoma and adenocarcinoma of the lung (2.29 and 2.18, respectively) and clear cell carcinoma of the kidney (2.73). Many of the findings were novel and could be revealed only by applying codes for specific histopathology. These data call for a closer description of familial aggregations and probing for the underlying genetic mechanisms.

Cancer risks among long-standing spouses

We estimated risks for concordant and discordant cancers in spouses in order to quantify cancer risks from the shared environment. The study was restricted to spouses who had one or more children in common and who lived together for at least 15 years after the first child's birth. The nation-wide Family-Cancer Database was used as the source of family and cancer data. Standardised incidence ratios were calculated for concordant and discordant cancers in spouses after 50 years of age. Among the 18 cancer sites considered, only three sites, stomach, lung and bladder, showed concordant increases of cancer among spouses, standardised incidence ratios ranging only from 1.19 to 1.38. Additionally, gastric and pancreatic cancer were associated among spouses, as did many cancers which were related to tobacco smoking or human papilloma virus infection. By contrast, standardised incidence ratios of colon, rectal, renal and skin cancers showed no increases among spouses. Shared lifestyle among family members seems to explain only a small proportion of familial cancer susceptibility. Because lifestyles are likely to differ more between parents and offspring than between spouses, familial cancer risks between parents and offspring are even more likely to be due to heritable than environmental effects.

Age-incidence relationships and time trends in cervical cancer in Sweden

Age-incidence relationships are informative of carcinogenic mechanisms. These have been previously assessed for cervical squamous cell carcinoma (SCC) but not for adenocarcinoma. The aim was to assess by means of age-, period- and cohort-specific analyses and Poisson regression modelling whether the two types of cervical cancer show an age-incidence maximum at a relatively young age, as shown in cross-sectional analyses. The Swedish Family-Cancer Database was used to analyse age-incidence relationships in cervical SCC and adenocarcinoma diagnosed in years 1958-1996, including a total of 15,118 and 1866 cases, respectively. Area of residence and socio-economic status were included in analyses because they were risk factors of cervical cancer. The analysis of cervical SCC confirmed an incidence maximum at ages 35-39 years. The data for adenocarcinoma also suggested a similar early age maximum but the curves differed extensively by birth cohort. The incidence of adenocarcinoma increased substantially at young age groups towards the end of follow-up. Endometrial adenocarcinoma and vaginal and vulvar SCC, which share some risk factors with cervical cancer, did not show an early age incidence maximum. The results also showed that there was a decrease in the incidence of cervical SCC around year 1960, almost 10 years before the organized population screening, probably due to introduced opportunistic pap testing. The benefits of the organized screening were observed as a further decline in the incidence rates. The unique age-incidence relationships in cervical cancer call for biological explanations.

Familial and second esophageal cancers: a nation-wide epidemiologic study from Sweden

A few case-control studies have been published on familial risks in esophageal cancer. Reliable data on familial risks are needed for prevention and clinical decisions. We used the nation-wide Swedish Family-Cancer Database on 10.1 million individuals and close to 6000 esophageal cancers to calculate standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for esophageal cancer in 0-66-year-old offspring by cancers in family members. Additionally, SIRs for second esophageal cancers were analyzed. The SIR for esophageal cancer was 3.91 (95% CI 1.55-7.35) when a parent presented with esophageal cancer and 4.91 (95% CI 1.77-9.62) when a parent presented with squamous cell carcinoma. The sibling risk for esophageal cancer was increased but was based on 1 pair only. The population-attributable proportion of familial esophageal cancer was 0.70%. Risks for second esophageal cancers were increased after upper aerodigestive tract, esophageal, stomach, larynx, and lung cancers. The data on second cancers suggest that environmental factors are important for esophageal cancer and probably contribute to the familial clustering. However, the high familial risk of 3.91 is unlikely without the involvement of heritable factors. The population-attributable proportion of familial esophageal cancer is small.

Familial cancer history in patients with carcinoma of the cervix uteri

OBJECTIVES

Several cancers show the tendency to aggregate in families. But the contribution of heredity to the causation of sporadic malignancies, like cervical cancer is unclear.

STUDY DESIGN

Seven hundred and thirty-seven women with operative treated cervical cancer (CX) were searched for familiar history of malignant tumours. Positive familial history was stated, if one first degree relative was affected by malignant tumour. The site of malignant tumour was stated and the mean age was compared.

RESULTS

Twenty-two percent of the women had malignancies at different sites in first degree relatives. In about one-half the mother, in 30% the father and in 11% more than one first degree relative was affected. Overall, first degree relatives of 21 patients (13%) had malignancies of the lungs or the oro-pharynx. Thirty-seven women had malignant tumours of the lower genital tract and 11 had invasive cervical cancer. Mean age of patients with positive familial history was the same as those without (43 versus 42 years) it. But, women whose first degree female relatives had cervical cancer were significantly younger than those with extragenital malignancies (37 versus 45 years). The mean 5-year survival rate was higher in patients with a positive familial cancer history (85.6% versus 74.6%; P=1.7).

CONCLUSIONS

The data suggest, that a small number of patients have a familial susceptibility for cervical cancer and probably for HPV-associated neoplasms. Further studies establishing the immune status and the search for genetic polymorphisms of these patients are required.

A population-based study of squamous cell vaginal cancer: HPV and cofactors

BACKGROUND

Little is known about the etiology of in situ or invasive squamous cell cancer of the vagina. It is thought that some vaginal cancers may have the same etiology as cervical cancer. It is also not known whether in situ and invasive vaginal cancer share the same etiologic factors. We conducted a study to evaluate risk factors for in situ and invasive vaginal cancer and their potential relationship to prior exposure to human papillomaviruses (HPV).

METHODS

A population-based case-control study included 156 women with squamous cell in situ or invasive vaginal cancer diagnosed between January 1981 and June 1998 and 2041 control women identified through random-digit dialing in western Washington state. Cases and controls were interviewed in person and provided blood samples; archival tumor tissue was retrieved for cases. Blood samples were tested for antibodies to HPV, and tumor tissue was tested for HPV DNA.

RESULTS

Women with vaginal cancer were more likely to have five or more lifetime sexual partners (OR = 3.1, 95% CI 1.9 to 4.9), to have an early age at first intercourse (<17 years OR = 2.0, 95% CI 1.2 to 3.5), and to be current smokers at diagnosis (OR = 2.1, 95% CI 1.4 to 3.1) than control women. Approximately 30% of all cases had been treated for a prior anogenital tumor, most often of the cervix. Prior hysterectomy was a risk factor only among women who had no history of prior anogenital cancer (OR = 3.9 95% CI 2.5 to 6.1). Antibodies to HPV16 L1 were strongly related to risk of vaginal cancer (OR = 4.3, 95% CI 3.0 to 6.2). We detected HPV DNA in tumor blocks from over 80% of the patients with in situ and 60% of the patients with invasive cancers.

CONCLUSIONS

In situ and invasive vaginal neoplasia have many of the same risk factors as cervical cancer, including a strong relationship to HPV infection. Women who have been treated for a prior anogenital cancer, particularly of the cervix, have a high relative risk, although low absolute risk, of being diagnosed with vaginal cancer.

Second primary cancers after anogenital, skin, oral, esophageal and rectal cancers: etiological links?

The Swedish Family-Cancer Database was used to analyze second cancers after oral, esophageal, rectal, cervical, genital and skin (squamous cell carcinoma) cancers. A strong and consistent association of second cancers was observed at all these sites, in men and women. As a novel finding, an association of rectal cancer with the human papillomavirus (HVP)-related cancers was shown. New evidence on an excess of skin cancer with the HPV-related cancers was also provided. As an epidemiological study, the associations were strong and often supported by a number of comparisons. These could not be explained by bias or long-term treatment related effects. However, whether the findings on rectal and skin cancer are due to HPV or other infections, transient or inherited depressed immune function or other constitutional factors remains to be established.