Influence of family size and birth order on risk of cancer: a population-based study

<p>Abstract</p> <p>Background</p> <p>Family size and birth order are known to influence the risk of some cancers. However, it is still unknown whether these effects change from early to later adulthood. We used the data of the Swedish Family-Cancer Database to further analyze these effects.</p> <p>Methods</p> <p>We selected over 5.7 million offspring with identified parents but no parental cancer. We estimated the effect of birth order and family size by Poisson regression adjusted for age, sex, period, region and socioeconomic status. We divided the age at diagnosis in two groups, below and over 50 years, to identify the effect of family size and birth order for different age periods.</p> <p>Results</p> <p>Negative associations for increasing birth order were found for endometrial, testicular, skin, thyroid and connective tissue cancers and melanoma. In contrast, we observed positive association between birth order and lung, male and female genital cancers. Family size was associated with decreasing risk for endometrial and testicular cancers, melanoma and squamous cell carcinoma; risk was increased for leukemia and nervous system cancer. The effect of birth order decreased for lung and endometrial cancer from age at diagnosis below to over 50 years. Combined effects for birth order and family size were marginally significant for thyroid gland tumors. Especially, the relative risk for follicular thyroid gland tumors was significantly decreased for increasing birth order.</p> <p>Conclusion</p> <p>Our findings suggest that the effect of birth order decreases from early to late adulthood for lung and endometrial cancer.</p

Does the time interval between first and last birth influence the risk of endometrial and ovarian cancer?

Background: Age at first and last birth and the number of children are known to influence the risk of endometrial and ovarian cancers. However, it remains unknown whether the difference in years between first and last childbirth plays a role. The Swedish Family-Cancer Database allowed us to carry out the largest study ever on reproductive factors in these cancers. Material and methods: We selected over 5.7 million women from the database. We estimated the effect of number of children, age at birth and difference between age at first and last birth by Poisson regression adjusted for age, period, region and socioeconomic status. Results: The risk for endometrial cancer is negatively associated with increasing number of children and increasing age at first as well as age at last birth. Weaker associations are found for ovarian cancer. Age at last birth is the factor that shows highest influence. A large difference in first and last childbirth shows a protective effect on the risk of endometrial cancer. Conclusion: Our findings suggest that the risk of endometrial cancer is significantly decreased for women having at least a difference of 10 years between their first and last birth. Ovarian cancer does not seem to be influenced by the time interval between first and last birth. (c) 2010 Elsevier Ltd. All rights reserved

Risk of breast cancer in families of multiple affected women and men

Family history of first and second-degree relatives is known to increase the risk for breast cancer. Less data are available on the risks between defined multiple affected close and distant relatives for which the reliability of data may be an issue. Data on affected males are sparse. These questions and the probable genetic models were addressed in this study by means of a nationwide Swedish Family-Cancer Database. We estimated the effect of family history of breast cancer by Poisson regression for women of at least 30 years of age after adjusting for age, period, region, socioeconomic status, number of children, and age at first birth. The results of the study showed that relative risk (RR) for breast cancer was associated with a first degree as well as second-degree family history. Having at least two female affected first-degree relatives increased the RR at least to 2.8, favoring an additive interaction. The risk was increased around ten times in women with both parents affected. When either a father or a mother was affected, the RRs were nearly identical (RR = 1.73 and 1.74, respectively). The RR for a woman increased more when a brother was affected (RR = 2.48) compared to when a sister was affected (RR = 1.87). Having an affected grandmother showed lower familial excess risks than having an affected half sister (RR = 1.27, and 1.26; and RR = 1.39, and 1.50; respectively, for maternal and paternal relatives). We concluded that when both parents were diagnosed with breast cancer, the risk for the daughter was increased tenfold. Having an affected brother showed a somewhat higher risk than having an affected sister. The data suggest that male breast cancer has a higher genetic basis than female breast cancer, which invites further search of the underlying mechanisms

Incidence of cancer of unknown primary in Sweden: analysis by location of metastasis.

Increasing incidences of cancer of unknown primary (CUP) have been observed in Sweden previously. However, it is not known how the incidence trends for specific locations of metastasis vary. Site-specific data are available on the basis of the ninth international classification of diseases. CUP patients were identified between 1987 and 2008 from the Swedish Family-Cancer Database. Malignant neoplasms of ill-defined sites were diagnosed in 4042 patients, 1976 developed metastasis in lymph nodes, 9615 had metastasis in specified organs, and in 8052 patients, the malignant neoplasm was diagnosed without further specification. Age-standardized incidence rates for 23 685 patients were analyzed using a direct method of standardization. Overall, the incidence of CUP decreased from 6.98 to 6.00 per 100 000 from 1987 to 2008. The number of patients diagnosed with metastasis in specified organs decreased, whereas the number of patients diagnosed with CUP without further specification increased from 2.65 to 3.02 per 100 000. With improvements in diagnostic methods and imaging techniques for identification of cancer, the incidences of CUP have been decreasing because primary tumors can be specified more often. Computed tomography is typically sensitive in detecting lung, kidney, and colorectal cancers, which are known to have a genetic link with CUP. Prostate-specific antigen testing is used to detect prostate cancer, for which bone is a common metastatic site. Liver metastases are common if the primary tumor is located in the colorectum. If the primary tumor is found, this cancer site replaces the diagnosis of CUP within the Cancer Register and therefore CUP incidence is decreased

Site-specific cancer deaths in cancer of unknown primary diagnosed with lymph node metastasis may reveal hidden primaries.

Cancer of unknown primary site (CUP) is a fatal cancer ranking among the five most common cancer deaths. CUP is diagnosed through metastases, which are limited to lymph nodes in some patients. Cause-specific survival data could guide the search for hidden primary tumors and help with therapeutic choices. The CUP patients were identified from the Swedish Cancer Registry between 1987 and 2008; 1444 patients had only lymph node metastasis of defined histology (adenocarcinoma, squamous cell or undifferentiated). Site-specific cancer deaths were analyzed by lymph node location and histology. Kaplan-Meier survival curves were compared with metastatic primary cancer at related sites. Among the patients with metastasis to head and neck lymph nodes, 117 (59.1% of the specific cancer deaths) died of lung tumors. Patients with axillary lymph node metastasis died of lung and breast tumors in equal proportions (40.2% each). Also, squamous cell CUP in head and neck lymph nodes was mainly associated with lung tumor deaths (53.1%). With a few exceptions, survival of CUP patients with lymph node metastasis was indistinguishable from survival of patients with metastatic primary cancer originating from the organs drained by those nodes. The association between lymph node CUP metastases with cancer deaths in the drained organ and the superimposable survival kinetics suggests that drained organs host hidden primaries. Importantly, half of all site-specific cancer deaths (266/530) were due to lung tumors. Thus, an intense search should be mounted to find lung cancer in CUP patients with lymph node metastases.© 2012 Wiley Periodicals, Inc

Prognostic impact of polymorphisms in the MYBL2 interacting genes in breast cancer

MYBL2 is a transcription factor, which regulates the expression of genes involved in cancer progression. In this study, we investigated whether putative functional variants in genes regulating MYBL2 (E2F1, E2F3 and E2F4) or in genes, which are regulated by MYBL2 (BCL2, BIRC5, COL1A1, COL1A2, COL5A2, ERBB2, CLU, LIN9 and TOP2A) affect breast cancer (BC) susceptibility and clinical outcome. Twenty-eight SNPs were genotyped in a population-based series of 782 Swedish BC cases and 1,559 matched controls. BC-specific survival analysis of BIRC5 suggested that carriers of the minor allele of rs8073069 and rs1042489 have a worse survival compared with the major homozygotes (HR 2.46, 95% CI 1.39-4.36 and HR 1.81, 95% CI 1.01-3.25, respectively). The poor survival was observed especially in women with aggressive tumours. Multivariate analysis supported the role of rs8073069 as an independent prognostic marker. For BCL2, minor allele carriers of rs1564483 were more likely to have hormone receptor-positive tumours than the major homozygotes. Another SNP in BCL2, rs4987852, was associated with tumour stages II-IV and histologic grade 3. In CLU, the minor allele carriers of rs9331888 were more likely to have tumours with regional lymph node metastasis and stages II-IV than the major homozygotes. In conclusion, our study suggests a role of genetic variation in BIRC5, BCL2 and CLU as progression and prognostic markers for BC, supporting previous studies based on the expression of the genes

Colorectal cancer risk and patients' survival: influence of polymorphisms in genes somatically mutated in colorectal tumors

The first two studies aiming for the high-throughput identification of the somatic mutation spectrum of colorectal cancer (CRC) tumors were published in 2006 and 2007. Using exome sequencing, they described 69 and 140 candidate cancer genes (CAN genes), respectively. We hypothesized that germline variants in these genes may influence CRC risk, similar to APC, which is causing CRC through germline and somatic mutations. After excluding the well-established CRC genes APC, KRAS, TP53, and ABCA1, we analyzed 35 potentially functional single-nucleotide polymorphisms (SNPs) in 10 CAN genes (OBSCN, MLL3, PKHD1, SYNE1, ERCC6, FBXW7, EPHB6/TRPV6, ELAC1/SMAD4, EPHA3, and ADAMTSL3) using KBiosciences Competitive AlleleaEuroSpecific PCR (TM) genotyping assays. In addition to CRC risk (1,399 CRC cases, 838 controls), we also considered the influence of the SNPs on patients' survival (406 cases). In spite of the fact that our in silico analyses suggested functional relevance for the studied genes and SNPs, our data did not support a strong influence of the studied germline variants on CRC risk and survival. The strongest association with CRC risk and survival was found for MLL3 (rs6464211, OR 1.50, p = 0.002, dominant model; HR 2.12, p = 0.020, recessive model). Two SNPs in EPHB6/TRPV6 (dominant model) showed marginal associations with survival (rs4987622 HR 0.58 p = 0.028 and rs6947538 HR 0.64, p = 0.036, respectively). Although somatic mutations in the CAN genes have been related to the development and progression of various types of cancers in several next-generation sequencing or expression analyses, our study suggests that the studied potentially functional germline variants are not likely to affect CRC risk or survival

Genetic variation in genes encoding for polymerase zeta subunits associates with breast cancer risk, tumour characteristics and survival

Chromosomal instability is a known hallmark of many cancers. DNA polymerases represent a group of enzymes that are involved in the mechanism of chromosomal instability as they have a central function in DNA metabolism. We hypothesized that genetic variation in the polymerase genes may affect gene expression or protein configuration and by that cancer risk and clinical outcome. We selected four genes encoding for the catalytic subunits of the polymerases beta, delta, theta and zeta (POLB, POLD1, POLQ and REV3L, respectively) and two associated proteins (MAD2L2 and REV1) because of their previously reported association with chromosomal instability and/or tumorigenesis. We selected potentially functional and most informative tagging single nucleotide polymorphisms (SNPs) for genotyping in a population-based series of 783 Swedish breast cancer (BC) cases and 1562 controls. SNPs that showed a significant association in the Swedish population were additionally genotyped in a Polish population consisting of 506 familial/early onset BC cases and 568 controls. SNPs in all three polymerase zeta subunit genes associated either with BC risk or prognosis. Two SNPs in REV3L and one SNP in MAD2L2 associated with BC risk: rs462779 (multiplicative model: OR 0.79, 95% CI 0.68-0.92), rs3204953 (dominant model: OR 1.28, 95% CI 1.05-1.56) and rs2233004 (recessive model: OR 0.49, 95% CI 0.28-0.86). Homozygous carriers of the minor allele C of the third SNP in REV3L, rs11153292, had significantly worse survival compared to the TT genotype carriers (HR 2.93, 95% CI 1.34-6.44). Minor allele carriers of two REV1 SNPs (rs6761391 and rs3792142) had significantly more often large tumours and tumours with high histological grade and stage. No association was observed for SNPs in POLB, POLQ and POLD1. Altogether, our data suggest a significant role of genetic variation in the polymerase zeta subunit genes regarding the development and progression of BC

Genetic Polymorphisms in Host Innate Immune Sensor Genes and the Risk of Nasopharyngeal Carcinoma in North Africa

Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world. It is an Epstein-Barr virus-associated malignancy with an unusual racial and geographical distribution. The host innate immune sensor genes play an important role in infection recognition and immune response against viruses. Therefore, we examined the association between polymorphisms in genes within a group of pattern recognition receptors (including families of Toll-like receptors, C-type lectin receptors, and retinoic acid-inducible gene I-like receptors) and NPC susceptibility. Twenty-six single-nucleotide polymorphisms (SNPs) in five pattern-recognition genes were genotyped in 492 North African NPC cases and 373 frequency-matched controls. TLR3_rs3775291 was the most significantly associated SNP (odds ratio [OR] 1.49; 95% confidence interval [95% CI] 1.11-2.00; P = 0.008; dominant model). The analysis showed also that CD209_rs7248637 (OR 0.69; 95% CI 0.52-0.93; P = 0.02; dominant model) and DDX58_rs56309110 (OR 0.70; 95% CI 0.51-0.98; P = 0.04) were associated with the risk of NPC. An 18% increased risk per allele was observed for the five most significantly associated SNPs, TLR3_rs3775291, CD209_rs7248637, DDX58_rs56309110, CD209_rs4804800, and MBL2_rs10824792, (p(trend) = 8.2 x 10(-4)). Our results suggest that genetic variation in pattern-recognition genes is associated with the risk of NPC. These preliminary findings require replication in larger studies