Serum selenium levels predict survival after breast cancer.

BACKGROUND: Studies have reported an inverse relationship between serum selenium levels and cancer incidence, but the impact of low serum selenium status on survival after a diagnosis of breast cancer has not been established. METHODS: We obtained a blood sample from 546 women diagnosed with a first primary invasive breast cancer between 2008 and 2015 in the region of Szczecin, Poland. Blood was collected after diagnosis, but prior to treatment. Serum selenium was quantified by mass spectroscopy and each patient was assigned to one of four categories (quartiles) based on the distribution in the entire cohort. Patients were followed from diagnosis to death over a mean follow-up of 3.8 years. Vital status was obtained by linkage to the Polish National Death Registry. RESULTS: The 5-year overall actuarial survival was 68.1% for women in the lowest (< 64.4 µg/L) and 82.5% for those in the highest (> 81.0 µg/L) quartile of serum selenium. In an adjusted analysis, the hazard ratio for death was 2.49 (95%CI 1.53-4.04; P = 0.0002) for patients in the lowest quartile of serum selenium, compared to those in all other quartiles. The effect of low selenium on breast cancer-specific mortality was stronger for women who were past smokers (HR 6.03; 95%CI 1.96-18.6; P = 0.0002). CONCLUSIONS: This study suggests that a selenium level in excess of 64.4 µg//L might be beneficial for women undergoing treatment for breast cancer and that selenium supplementation to achieve this level may favorably impact the outcome. Further studies are needed to confirm this association and to evaluate the impact of selenium supplementation on breast cancer survival among women with low post-diagnostic selenium levels.

The impact of an expanded genetic testing program and selective oophorectomy on the incidence of ovarian cancer in West Pomerania.

The aim of the study was to evaluate the impact of a regional population-based genetic testing program on the incidence of ovarian cancer in West Pomerania. Between 1999 and 2010, a total of 37,552 women ages 35 to 70 were tested for three BRCA1 founder mutations at the outpatient genetics clinic of the Pomeranian Medical University in Szczecin, Poland. A total of 641 women were found to carry a mutation (1.7%) and of these, 220 had a prophylactic oophorectomy (34.3%). A total of 12 women had an occult cancer diagnosed at the time of prophylactic oophorectomy (5.5%). We estimate that 26 more ovarian cancers would have been diagnosed by January 2015 in the absence of these oophorectomies and that an additional 25 cancers will be prevented in the future (total 51). During this period, 1611 ovarian cancers were diagnosed in the region; therefore we estimate that approximately 1.6% of ovarian cancers were prevented between 1999 and 2015 by our genetic testing program. We conclude that the prophylactic oophorectomies performed between 1999 and 2010 as a result of widespread BRCA1 mutation testing have reduced the incidence of ovarian cancer in Pomerania by a small amount (about 1.6%), and that the impact of genetic testing will increase in the coming years.

Cumulative effects of genetic markers and the detection of advanced colorectal neoplasias by population screening.

Genetic markers associated with colorectal cancer may be used in population screening for the early identification of patients at elevated risk of disease. We genotyped 3059 individuals with no cancer family history for eight markers previously associated with colorectal cancer. After colonoscopy, the genetic profile of cases with advanced colorectal neoplasia (213) was compared with the rest (2846). rs2066847 and rs6983267 were significantly associated with the risk of advanced colorectal neoplasia but with limited effect on their own [odds ratio (OR) 1.59; 95% confidence interval (CI) 1.02-2.41; p = 0.033 and OR 1.45; 95% CI 1.02-2.12; p = 0.044, respectively]. Cumulative effects, in contrast, were associated with high risk: the combination of rs2066847, rs6983267, rs4779584, rs3802842 and rs4939827 minimized the number of markers considered, while maximizing the relative size of the carrier group and the risk associated to it, for example, for at least two cumulated risk markers, OR is 2.57 (95% CI 1.50-4.71; corrected p-value 0.0079) and for three or more, OR is 3.57 (95% CI 1.91-6.96; corrected p-value 0.00074). The identification of cumulative models of - otherwise - low-risk markers could be valuable in defining risk groups, within an otherwise low-risk population (no cancer family history).

Mutations predisposing to breast cancer in 12 candidate genes in breast cancer patients from Poland.

A number of genes other than BRCA1 and BRCA2 have been associated with breast cancer predisposition, and extended genetic testing panels have been proposed. It is of interest to establish the full spectrum of deleterious mutations in women with familial breast cancer.We performed whole-exome sequencing of 144 women with familial breast cancer and negative for 11 Polish founder mutations in BRCA1, CHEK2 and NBS1, and we evaluated the sequences of 12 known breast cancer susceptibility genes. A truncating mutation in a breast cancer gene was detected in 24 of 144 women (17%) with familial breast cancer. A BRCA2 mutation was detected in 12 cases, a (non-founder) BRCA1 mutation was detected in 5 cases, a PALB2 mutation was detected in 4 cases and an ATM mutation was detected in 2 cases. Polish women with familial breast cancer who are negative for founder mutations in BRCA1, CHEK2 and NBS1 should be fully screened for mutations in BRCA1, BRCA2 and PALB2. The PALB2 founder mutation c.509_519delGA should be included in the panel of Polish founder mutations.

Recurrent mutations of BRCA1 and BRCA2 in Poland: an update.

Three founder alleles of BRCA1 (C61G, 4153delA, 5382insC) were reported in Poland in 2000, and these three mutations have comprised the standard testing panel used throughout the country. However, since 2000, other recurrent mutations of BRCA1 and BRCA2 have been reported. To establish if the inclusion of one or more of these mutations will increase the sensitivity of the standard test panel, we studied 1164 Polish women with unselected breast cancer diagnosed at age of 50 or below. All women were genotyped for 12 recurrent mutations of BRCA1 and BRCA2. We identified a mutation in 83 of 1164 patients (7.1%) including 61 women with one of the original three mutations (C61G, 4153delA, 5382insC) and 22 women with a different mutation (1.9%). Three new mutations (3819del5, 185delAG and 5370C>T) were seen in multiple families. By including these three mutations in the extended panel, the mutant frequency increased from 5.2 to 6.7%. Polish women with breast cancer diagnosed at age of 50 or below should be screened with a panel of six founder mutations of BRCA1 (C61G, 4153delA, 5382insC, 3819del5, 185delAG and 5370C>T).

Xeroderma pigmentosum genes and melanoma risk.

Xeroderma pigmentosum is a rare autosomal recessive disease that is associated with a severe deficiency in nucleotide excision repair. The presence of a distinct the nucleotide excision repair (NER) mutation signature in melanoma suggests that perturbations in this critical repair process are likely to be involved with disease risk. We hypothesized that persons with polymorphic NER gene(s) are likely to have reduced NER activity and are consequently at an increased risk of melanoma development. We assessed the association between 94 SNPs within seven XP genes (XPA-XPG) and the melanoma risk in the Polish population. We genotyped 714 unselected melanoma patients and 1,841 healthy adults to determine if there were any polymorphisms differentially represented in the disease group. We found that a significantly decreased risk of melanoma was associated with the Xeroderma pigmentosum complementation (XPC) rs2228000_CT genotype (odds ratio [OR] = 0.15; p < 0.001) and the rs2228000_TT genotype (OR = 0.11; p < 0.001) compared to the reference genotype. Haplotype analysis within XPC revealed the rs2228001_A + G1475A_G + G2061A_A + rs2228000_T + rs3731062_C haplotype (OR = 0.26; p < 0.05) was associated with a significantly decreased disease risk. The haplotype analysis within the Xeroderma pigmentosum group D (XPD) showed a modest association between two haplotypes and a decrease in melanoma risk. There were no major differences between the prevalence of the XP polymorphisms among young or older patients with melanoma. Linkage disequilibrium of XPC: rs2228001, G1475A, G2061A, rs2228000 and rs3731062 was found. The data from our study support the notion that only XPC and XPD genes are associated with melanoma susceptibility.

A personalised approach to prostate cancer screening based on genotyping of risk founder alleles.

BACKGROUND: To evaluate whether genotyping for 18 prostate cancer founder variants is helpful in identifying high-risk individuals and for determining optimal screening regimens. METHODS: A serum PSA level was measured and a digital rectal examination (DRE) was performed on 2907 unaffected men aged 40-90. Three hundred and twenty-three men with an elevated PSA (≥4 ng ml⁻¹) or an abnormal DRE underwent a prostate biopsy. All men were genotyped for three founder alleles in BRCA1 (5382insC, 4153delA and C61G), for four alleles in CHEK2 (1100delC, IVS2+1G>A, del5395 and I157T), for one allele in NBS1 (657del5), for one allele in HOXB13 (G84E), and for nine low-risk single-nucleotide polymorphisms (SNPs). RESULTS: On the basis of an elevated PSA or an abnormal DRE, prostate cancer was diagnosed in 135 of 2907 men (4.6%). In men with a CHEK2 missense mutation I157T, the cancer detection rate among men with an elevated PSA or an abnormal DRE was much higher (10.2%, P=0.0008). The cancer detection rate rose with the number of SNP risk genotypes observed from 1.2% for men with no variant to 8.6% for men who carried six or more variants (P=0.04). No single variant was helpful on its own in predicting the presence of prostate cancer, however, the combination of all rare mutations and SNPs improved predictive power (area under the curve=0.59; P=0.03). CONCLUSION: These results suggest that testing for germline CHEK2 mutations improves the ability to predict the presence of prostate cancer in screened men, however, the clinical utility of incorporating DNA variants in the screening process is marginal.

An inherited NBN mutation is associated with poor prognosis prostate cancer.

BACKGROUND: To establish the contribution of eight founder alleles in three DNA damage repair genes (BRCA1, CHEK2 and NBS1) to prostate cancer in Poland, and to measure the impact of these variants on survival among patients. METHODS: Three thousand seven hundred fifty men with prostate cancer and 3956 cancer-free controls were genotyped for three founder alleles in BRCA1 (5382insC, 4153delA, C61G), four alleles in CHEK2 (1100delC, IVS2+1G>A, del5395, I157T), and one allele in NBS1 (657del5). RESULTS: The NBS1 mutation was detected in 53 of 3750 unselected cases compared with 23 of 3956 (0.6%) controls (odds ratio (OR)=2.5; P=0.0003). A CHEK2 mutation was seen in 383 (10.2%) unselected cases and in 228 (5.8%) controls (OR=1.9; P<0.0001). Mutation of BRCA1 (three mutations combined) was not associated with the risk of prostate cancer (OR=0.9; P=0.8). In a subgroup analysis, the 4153delA mutation was associated with early-onset (age ≤ 60 years) prostate cancer (OR=20.3, P=0.004). The mean follow-up was 54 months. Mortality was significantly worse for carriers of a NBS1 mutation than for non-carriers (HR=1.85; P=0.008). The 5-year survival for men with an NBS1 mutation was 49%, compared with 72% for mutation-negative cases. CONCLUSION: A mutation in NBS1 predisposes to aggressive prostate cancer. These data are relevant to the prospect of adapting personalised medicine to prostate cancer prevention and treatment.

The contribution of founder mutations in BRCA1 to breast cancer in Belarus.

Mutations in the BRCA1 gene increase susceptibility to both breast and ovarian cancer. In some countries, including several in Eastern Europe, founder mutations in the BRCA1 gene are responsible for a significant proportion of breast cancer cases. To estimate the hereditary proportion of breast cancer in Belarus, we sought the presence of any of three founder mutations in BRCA1 (4153delA, 5382insC and C61G) in 500 unselected cases of breast cancer. These mutations have previously been identified in breast/ovarian cancer families from Belarus and from other Slavic countries, including Poland and Russia. One of the three founder mutations in BRCA1 was present in 38 of 500 unselected cases of breast cancer (7.6%). A mutation was found in 12.6% of women diagnosed before age 50 and 5.6% of women diagnosed after age 50. A mutation was identified in 2 of 251 newborn controls (0.8%). The hereditary proportion of breast cancers in Belarus is among the highest of any countries studied to date.

Effect of CHEK2 missense variant I157T on the risk of breast cancer in carriers of other CHEK2 or BRCA1 mutations.

BACKGROUND: Carriers of heterozygous mutations in CHEK2 or BRCA1 are at increased risk of breast cancer. These mutations are rare and a very small number of women in a population will carry two mutations. However, it is of interest to estimate the breast cancer risks associated with carrying two mutations because this information may be informative for genetic counsellors and may provide clues to the carcinogenic process. METHODS: We genotyped 7782 Polish breast cancer patients and 6233 controls for seven founder mutations in BRCA1 and CHEK2. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for the mutations, singly and in combination. RESULTS: Of the 7782 women with breast cancer, 1091 had one mutation (14.0%) and 37 had two mutations (0.5%). Compared to controls, the odds ratio for a BRCA1 mutation in isolation was 13.1 (95% CI 8.2 to 21). The odds ratio was smaller for BRCA1 mutation carriers who also carried a CHEK2 mutation (OR 6.6, 95% CI 1.5 to 29), but the difference was not statistically significant. In contrast, the odds ratio for women who carried two CHEK2 mutations (OR 3.9, 95% CI 1.5 to 10) was greater than that for women who carried one CHEK2 mutation (OR 1.9, 95% CI 1.6 to 2.1). The odds ratio for women who carried both a truncating mutation and the missense mutation in CHEK2 was 7.0 (95% CI 0.9 to 56) and was greater than for women who carried the truncating mutation alone (OR 3.3, 95% CI 2.4 to 4.3) or the missense mutation alone (OR 1.6, 95% CI 1.4 to 1.9), but the difference was not statistically significant. CONCLUSION: Our study suggests that the risk of breast cancer in carriers of a deleterious CHEK2 mutation is increased if the second allele is the I157T missense variant. However, the presence of a CHEK2 mutation in women with a BRCA1 mutation may not increase their risk beyond that of the BRCA1 mutation alone. These suggestive findings need to be verified in other studies.

Cancer risks in first-degree relatives of CHEK2 mutation carriers: effects of mutation type and cancer site in proband.

It is important to have accurate knowledge of the range of cancers associated with various CHEK2 mutations, and of the lifetime risks of cancer associated with each. We wished to establish the relationship between family history, mutation type and cancer risk in families with a CHEK2 mutation. We obtained a blood sample and pedigree information from 2012 unselected women with breast cancer, from 2007 men with prostate cancer and from 1934 patients with colon cancer, from hospitals throughout Poland. Genetic testing was carried out for four founder CHEK2 mutations on all 5953 specimens and 533 carriers were identified. We estimated the risk to age 75 for any cancer in the 2544 first-degree relatives to be 22.3%. After adjusting for mutation type, the risk of breast cancer was much higher among relatives of probands with breast cancer than among relatives of patients with prostate or colon cancer (HR=3.6; 95% CI=2.1-6.2; P=0.0001). Similarly, the risk of prostate cancer was higher among relatives of probands with prostate cancer than among relatives of patients with breast or colon cancer (HR=4.4; 95% CI=2.2-8.7; P=0.0001) and the risk of colon cancer was higher among relatives of probands with colon cancer than among relatives of patients with prostate or breast cancer (HR=4.2; 95% CI=2.4-7.8; P=0.0001). These analyses suggest that the risk of cancer in a carrier of a CHEK2 mutation is dependent on the family history of cancer.

Vitamin D receptor variants and breast cancer risk in the Polish population.

The aim of the study was to determine whether four VDR gene single nucleotide polymorphisms (SNPs: rs1544410, rs731236, rs10735810 and rs4516035) are associated with breast cancer risk in Polish population. Two independent series of female patients were employed: 960 consecutive breast cancer cases, and 800 unselected early onset cases diagnosed under the age of 51. The control group for the consecutive breast cancer cases consisted of 960 healthy, age-matched women with a negative cancer family history. 550 healthy women, aged 51 or less, with negative cancer family history were selected as the independent controls for the early onset breast cancer cases. The frequencies of the VDR polymorphisms in the unselected cases when compared to the respective control population failed to reveal any association between the individual SNPs and disease. Examination of the group of early-onset patients, revealed an association between rs10735810 and increased breast cancer risk. Heterozygous carriers for the change had an OR = 1.73 (95% CI 1.33-2.26, P < 0.0001) and homozygous carriers OR = 2.34 (95% CI 1.71-3.21, P < 0.0001). The remaining three examined SNPs failed to show any association with disease risk. In summary, this study has identified an association between the VDR gene and early onset breast cancer risk in the Polish population.

Estrogen receptor status in CHEK2-positive breast cancers: implications for chemoprevention.

To investigate the relationship between CHEK2 mutation status and estrogen receptor (ER) status in unselected cases of early-onset breast cancer from Poland, we screened 4441 women diagnosed with breast cancer younger than 51 years and 7217 controls for three inherited mutations in CHEK2 (1100delC, IVS2+1G>A, del5395). ER status was compared between CHEK2-positive and CHEK2-negative breast cancer cases. A truncating mutation in CHEK2 was seen in 140 of 4441 cases and in 70 of 7217 controls [odds ratio (OR) = 3.3; 95% CI = 2.5-4.4; p < 0.0001]. ER status was available for 92 of 140 mutation carriers and for 3001 of 4301 non-carriers with breast cancer. The OR was higher for ER-positive cancers (OR = 3.9; 95% CI = 2.7-5.4; p < 0.0001) than for ER-negative cancers (OR = 2.1; 95% CI = 1.3-3.3; p = 0.002). Sixty-six of the 92 breast cancers in carriers of CHEK2 truncating mutations were ER positive compared with 1742 of the 3001 breast cancers in non-carriers (72% vs 58%; p = 0.01). Women with a CHEK2 mutation face a fourfold increase in the risk of ER-positive breast cancer and might be candidates for tamoxifen chemoprevention.

Common variants of DNA repair genes and malignant melanoma.

In the current study, we evaluated the possible associations of seven common variants of the DNA repair and cell cycle control genes BRCA2 and CHEK2 with malignant melanoma (MM). We genotyped 630 unselected MM patients and over 3700 controls (newborns, age- and sex-matched healthy adults with negative cancer family histories, and the adults selected at random by family doctors) for the prevalence of three common variants of the BRCA2 (T1915M, N991D and N372H) and four common variants of the CHEK2 (1100delC, VS2+1G --> A, I157T and del5395). Our study strongly suggests that the common variant of the BRCA2 gene -- the N991D variant is associated with malignant melanoma risk (OR=1.8, p=0.002 after Bonferroni correction). Patients homozygote for the N991D variant were present in 0.32% of cases and only 0.13% of controls. The other variants studied were not over-represented among MM patients when compared to the general population. In conclusion, we report an increased melanoma risk among carriers of the N991D change of the BRCA2 and no association of the CHEK2 changes with malignant melanoma.

A large germline deletion in the Chek2 kinase gene is associated with an increased risk of prostate cancer.

BACKGROUND: Germline mutations in the Chek2 kinase gene (CHEK2) have been associated with a range of cancer types. Recently, a large deletion of exons 9 and 10 of CHEK2 was identified in several unrelated patients with breast cancer of Czech or Slovak origin. The geographical and ethnic extent of this founder allele has not yet been determined. PARTICIPANTS AND METHODS: We assayed for the presence of this deletion, and of three other CHEK2 founder mutations, in 1864 patients with prostate cancer and 5496 controls from Poland. RESULTS: The deletion was detected in 24 of 5496 (0.4%) controls from the general population, and is the most common CHEK2 truncating founder allele in Polish patients. The deletion was identified in 15 of 1864 (0.8%) men with unselected prostate cancer (OR 1.9; 95% CI 0.97 to 3.5; p = 0.09) and in 4 of 249 men with familial prostate cancer (OR 3.7; 95% CI 1.3 to 10.8; p = 0.03). These ORs were similar to those associated with the other truncating mutations (IVS2+1G-->A, 1100delC). CONCLUSION: A large deletion of exons 9 and 10 of CHEK2 confers an increased risk of prostate cancer in Polish men. The del5395 founder deletion might be present in other Slavic populations, including Ukraine, Belarus, Russia, Baltic and Balkan countries. It will be of interest to see to what extent this deletion is responsible for the burden of prostate cancer in other populations.

A common variant of CDKN2A (p16) predisposes to breast cancer.

BACKGROUND: A common missense variant of the CDKN2A gene (A148T) predisposes to malignant melanoma in Poland. An association between malignant melanoma and breast cancer has been reported in several families with CDKN2A mutations, OBJECTIVE: To determine whether this variant also predisposes to breast cancer. METHODS: Genotyping was undertaken in 4209 cases of breast cancer, unselected for family history, from 18 hospitals throughout Poland and in 3000 controls. RESULTS: The odds ratio (OR) associated with the CDKN2A allele for women diagnosed with breast cancer before the age of 50 was 1.5 (p = 0.002) and after age 50 it was 1.3 (p = 0.2). The effect was particularly strong for patients diagnosed at or before the age of 30 (OR = 3.8; p = 0.0002). CONCLUSIONS: CDKN2A appears to be a low penetrance breast cancer susceptibility gene in Poland. The association should be confirmed in other populations.

NBS1 is a prostate cancer susceptibility gene.

To evaluate whether an inactivating mutation in the gene for the Nijmegen breakage syndrome (NBS1) plays a role in the etiology of prostate cancer, we compared the prevalence of the 657del5 NBS1 founder allele in 56 patients with familial prostate cancer, 305 patients with nonfamilial prostate cancer, and 1500 control subjects from Poland. Loss of heterozygosity analysis also was performed on DNA samples isolated from 17 microdissected prostate cancers, including 8 from carriers of the 657del5 mutation. The NBS1 founder mutation was present in 5 of 56 (9%) patients with familial prostate cancer (odds ratio, 16; P < 0.0001), 7 of 305 (2.2%) patients with nonfamilial prostate cancer (odds ratio, 3.9; P = 0.01), and 9 of 1500 control subjects (0.6%). The wild-type NBS1 allele was lost in seven of eight prostate tumors from carriers of the 657del5 allele, but loss of heterozygosity was seen in only one of nine tumors from noncarriers (P = 0.003). These findings suggest that heterozygous carriers of the NBS1 founder mutation exhibit increased susceptibility to prostate cancer and that the cancers that develop in the prostates of carriers are functionally homozygous for the mutation.

NOD2 variants and the risk of malignant melanoma.

Both hereditary and environmental factors are important in the aetiology of malignant melanoma. Among the risk factors for malignant melanoma are immunodeficiency and immunosuppression. The recently identified NOD2 gene is involved in the regulation of immune function through activation of the transcription factor nuclear factor-kappaB (NF-kappaB). Three common NOD2 mutations -- 3020insC, G908R and R702W -- have been shown to be associated with chronic inflammatory disease such as Crohn's disease, the 3020insC also with human malignancy colorectal cancer. We examined the frequency of the NOD2 variants in 424 patients with malignant melanoma and 649 controls. The 3020insC mutation was present in 6.9% of unselected cases and 7% of the controls (odds ratio (OR) 1.0; P not significant). The mutation was present in 6.8% of 162 cases diagnosed under the age of 50 and in 7.1% of cases diagnosed after the age of 50. A mutation was present in the index case in 5% of 40 familial melanomas (OR 0.7; P not significant). There were no statistically significant differences between prevalence of G908R and R702W in malignant melanoma patients and controls. In conclusion, the three common NOD2 mutations are not associated with increased risk of development of malignant melanoma.

Optimization of experimental conditions for RNA-based sequencing of MLH1 and MSH2 genes.

The most sensitive technique for the detection of germline mutations is exon by exon sequencing of the gene under investigation using genomic DNA as a template for analysis. This approach, however, has cost and sensitivity limitations that can, at least in part, be overcome by RNA-based analysis. Germline mutations of MLH1 and MSH2 are the most frequent cause of the inherited susceptibility to colorectal and other epithelial cancers known as hereditary non-polyposis colorectal cancer (HNPCC). We compared the analysis of the MLH1 and MSH2 genes using mRNA and genomic DNA as starting material from 21 HNPCC patients. All samples were investigated by RT-PCR, sequencing of cDNA and simultaneous sequencing of genomic DNA. The cDNA was generated using specific primers complementary to the ends of MLH1 and MSH2 genes, respectively. Mutations in MLH1 and MSH2 were detected in 11 out of 21 unrelated patients. In 10 out of 11 cases, mutations were detected independently of the type of primers used for reverse transcription (RT). One novel missense mutation (K751R) in MLH1 was detected using this method. One nonsense mutation (E205X) in MSH2 was only detectable when RT was performed using MSH2 gene-specific primers. Shorter PCR products indicative of alternatively spliced transcripts were not observed when MLH1 or MSH2 specific cDNA RT primers were employed to generate template, except in one case where exon skipping was observed for exons 9 and 10. In this report we demonstrate that primers specific for RT of MLH1 and MSH2 are crucial for increasing the sensitivity of cDNA analysis. DNA sequencing using RNA as a basis for template construction may be a valuable and economical alternative to genomic DNA sequencing.