Efficacy of subsequent chemotherapy for patients with BRCA1/2-mutated recurrent epithelial ovarian cancer progressing on olaparib versus placebo maintenance: post-hoc analyses of the SOLO2/ENGOT Ov-21 trial.

BACKGROUND: In the SOLO2 trial (ENGOT Ov-21; NCT01874353), maintenance olaparib in patients with platinum-sensitive relapsed ovarian cancer (PSROC) and BRCA mutation significantly improved progression-free survival (PFS) and prolonged overall survival (OS). Following disease progression on olaparib, efficacy of subsequent chemotherapy remains unknown. PATIENTS AND METHODS: We conducted a post-hoc hypothesis-generating analysis of SOLO2 data to determine the efficacy of different chemotherapy regimens following RECIST disease progression in patients who received olaparib or placebo. We evaluated time to second progression (TTSP) calculated from the date of RECIST progression to the next progression/death. RESULTS: The study population comprised 147 patients who received chemotherapy as their first subsequent treatment after RECIST progression. Of these, 69 (47%) and 78 (53%) were originally randomized to placebo and olaparib arms, respectively. In the placebo-treated cohort, 27/69 and 42/69 received non-platinum and platinum-based chemotherapy, respectively, compared with 24/78 and 54/78, respectively, in the olaparib-treated cohort. Among patients treated with chemotherapy (N = 147), TTSP was significantly longer in the placebo than in the olaparib arm: 12.1 versus 6.9 months [hazard ratio (HR) 2.17, 95% confidence interval (CI) 1.47-3.19]. Similar result was obtained on multivariable analysis adjusting for prognostic factors at RECIST progression (HR 2.13, 95% CI 1.41-3.22). Among patients treated with platinum-based chemotherapy (n = 96), TTSP was significantly longer in the placebo arm: 14.3 versus 7.0 months (HR 2.89, 95% CI 1.73-4.82). Conversely, among patients treated with non-platinum-based chemotherapy (n = 51), the TTSP was comparable in the placebo and olaparib arms: 8.3 versus 6.0 months (HR 1.58, 95% CI 0.86-2.90). CONCLUSIONS: Following progression from maintenance olaparib in the recurrent setting, the efficacy of platinum-based subsequent chemotherapy seems to be reduced in BRCA1/2-mutated patients with PSROC compared to patients not previously receiving poly (ADP-ribose) polymerase inhibitors (PARPi). The optimal strategy for patients who relapse after PARPi is an area of ongoing research.

The impact of olaparib dose reduction and treatment interruption on treatment outcome in the SOLO2/ENGOT-ov21 platinum-sensitive recurrent ovarian cancer.

BACKGROUND: Maintenance treatment with poly (ADP-ribose) polymerase (PARP) inhibitor is now the standard of care in patients with BRCA-mutated platinum-sensitive recurrent ovarian cancer following response to chemotherapy. In the SOLO2 trial, adverse event (AE)-associated olaparib interruption, dose reduction, and discontinuation occurred in 50%, 28%, and 17% of patients, respectively. We used data from the SOLO2 trial to evaluate the impact of dose alterations on survival outcomes and identified baseline characteristics associated with dose alteration. PATIENTS AND METHODS: We computed relative dose intensity (RDI) defined as the received dose as a percentage of the standard dose (300 mg twice a day) during the first 12 weeks on treatment. Patients were categorized into RDI >98%, RDI 90%-98%, and RDI <90%. The association between RDI categories with progression-free survival (PFS) and overall survival (OS) were examined using a 12-week landmark Cox regression analysis. Logistic regression analysis was used to correlate baseline factors with RDI at 12 weeks. RESULTS: In patients on olaparib included in the landmark analysis (n = 185), the mean 12-week RDI was 91.4%. There was no significant difference across 12-week RDI >98% (n = 110), 90%-98% (n = 29), and <90% (n = 45) categories for PFS (median, 14.2 versus 19.3 versus 34.4 months; P = 0.37) and OS (median, 49.7 versus 49.5 versus 54.1 months; P = 0.84). Risk of RDI ≤90% increased with baseline performance status 1 [odds ratio (OR): 2.54; 95% confidence interval (CI): 1.11-5.82] any nausea (OR: 3.17; 95% CI: 0.9-11.23), and with body weight ≤70 kg (OR: 1.86; 95% CI: 0.92-3.76). CONCLUSIONS: Dose reduction and interruption for the management of olaparib-associated AEs during the first 12 weeks did not impact on PFS and OS. When counselling patients requiring dose reductions or interruptions due to AEs, the results of this study will help assure patients that their outcomes will not be adversely affected.

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 risk of breast cancer in BRCA1 and BRCA2 mutation carriers without a first-degree relative with breast cancer.

The objective of this study was to estimate the lifetime risk of breast cancer in women with a BRCA1 or BRCA2 mutation with and without at least 1 first-degree relative with breast cancer. A total of 2835 women with a BRCA1 or BRCA2 mutation were followed. Age- and gene-specific breast cancer rates were calculated. The relative risks of breast cancer for subjects with a family history of breast cancer, compared to no family history were calculated. The mean age at baseline was 41.1 years, and they were followed for a mean of 6.0 years. The estimated penetrance of breast cancer to age 80 years was 60.8% for BRCA1 and 63.1% for BRCA2. For all BRCA carriers, the penetrance of breast cancer to age 80 for those with no first-degree relative with breast cancer was 60.4% and 63.3% for those with at least 1 first-degree relative with breast cancer. The risk of breast cancer for BRCA carriers with no first-degree relative with breast cancer is substantial, and as a result, clinical management for these women should be the same as those for women with an affected relative.

New EPCAM founder deletion in Polish population.

It is well known that founder mutations associated with cancer risk have useful implications for molecular diagnostics. We report the presence of a founder mutation in EPCAM involved in the etiology of Lynch syndrome (LS). The mutation extends nearly 8.7 kb (c.858 + 2478_*4507del) and is shared by 8 Polish families. Family members suffered almost exclusively from colorectal cancer; however, pancreatic and gastric cancers were also apparent. Next to mutations c. 2041G>A in MLH1 gene and c.942+3A>T in MSH2, the deletion mutation encompassing EPCAM is one of the most common causative changes responsible for LS in Poland.

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.

The impact of oophorectomy on survival after breast cancer in BRCA1-positive breast cancer patients.

The aim of the study is to identify treatments which predict survival for women with a BRCA1 mutation, including oophorectomy and chemotherapy. 476 women with stage I to stage III breast cancer who carried a BRCA1 mutation were followed from diagnosis until April 2015. Information on treatment was obtained from chart review and patient questionnaires. Dates of death were obtained from the Poland vital statistics registry. Survival curves were compared for different subgroups according to treatment received. Predictors of overall survival were determined using the Cox proportional hazards model. The ten-year overall survival was 78.3 % (95 % CI 74.2-82.6 %) and the ten-year breast cancer-specific survival was 84.2 % (95 % CI 80.5-88.0 %). Sixty-two patients died of breast cancer, 14 patients died of ovarian cancer, and 2 patients died of peritoneal cancer. Oophorectomy was associated with a significant reduction in all-cause mortality in the entire cohort (adjusted HR = 0.41; 95 % CI 0.24-0.69; p = 0.0008) and in breast cancer-specific mortality among ER-negative breast cancer patients (HR = 0.44; 95 % CI 0.22-0.89; p = 0.02). Among women with breast cancer and a BRCA1 mutation, survival is greatly improved by oophorectomy due to the prevention of deaths from both breast and ovarian cancer.

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).

Pathologic complete response to neoadjuvant cisplatin in BRCA1-positive breast cancer patients.

The aim of this study is to estimate the frequency of pathologic complete response (pCR) after neoadjuvant treatment with cisplatin chemotherapy in women with breast cancer and a BRCA1 mutation. One hundred and seven women with breast cancer and a BRCA1 mutation, who were diagnosed with stage I to III breast cancer between December 2006 and June 2014, were treated with cisplatin 75 mg/m(2) every 3 weeks for four cycles, followed by mastectomy and conventional chemotherapy. Information was collected on clinical stage, grade, hormone receptor status, and Her2neu status prior to treatment. pCR was determined by review of surgical specimens. One hundred and seven patients were enrolled in the study, including 93 patients who were treated for first primary breast cancer and 14 patients who had previously received treatment for a prior cancer. A pCR was observed in 65 of the 107 patients (61 %). Platinum-based chemotherapy is effective in a high proportion of patients with BRCA1-associated breast cancer.

A prior diagnosis of breast cancer is a risk factor for breast cancer in BRCA1 and BRCA2 carriers.

BACKGROUND: The risk of breast cancer in carriers of BRCA1 and BRCA2 mutations is influenced by factors other than the genetic mutation itself. Modifying factors include a woman's reproductive history and family history of cancer. Risk factors are more likely to be present in women with breast cancer than in women without breast cancer, and therefore the risk of cancer in the two breasts should not be independent. It is not clear to what extent modifying factors influence the risk of a first primary or a contralateral breast cancer in BRCA carriers. METHODS: We conducted a matched case-control study of breast cancer among 3920 BRCA1 or BRCA2 mutation carriers. We asked whether a past history of breast cancer in the contralateral breast was a risk factor for breast cancer. RESULTS: After adjustment for age, country of residence, and cancer treatment, a previous cancer of the right breast was found to be a significant risk factor for cancer of the left breast among BRCA1 or BRCA2 carriers (relative risk: 2.1; 95% confidence interval: 1.4 to 3.0; p < 0.0001). CONCLUSIONS: In a woman with a BRCA1 or BRCA2 mutation who is diagnosed with breast cancer, the risk of cancer in the contralateral breast depends on the first diagnosis. That observation supports the hypothesis that there are important genetic or non-genetic modifiers of cancer risk in BRCA carriers. Discovering risk modifiers might lead to greater personalization of risk assessment and management recommendations for BRCA-positive patients.

Survival from breast cancer in patients with CHEK2 mutations.

The purpose of this study is to estimate 10-year survival rates for patients with early onset breast cancer, with and without a CHEK2 mutation and to identify prognostic factors among CHEK2-positive breast cancer patients. 3,592 women with stage I to stage III breast cancer, diagnosed at or below age 50, were tested for four founder mutations in the CHEK2 gene. Information on tumor characteristics and on treatments received was retrieved from medical records. Dates of death were obtained from the Poland Vital Statistics Registry. Survival curves were generated for the mutation-positive and -negative sub-cohorts. Predictors of survival were determined among CHEK2 carriers using the Cox proportional hazards model. 3,592 patients were eligible for the study, of whom 140 (3.9 %) carried a CHEK2-truncating mutation and 347 (9.7 %) carried a missense mutation. The mean follow-up was 8.9 years. The 10-year survival for all CHEK2 mutation carriers was 78.8 % (95 % CI 74.6-83.2 %) and for non-carriers was 80.1 % (95 % CI 78.5-81.8 %). Among women with a CHEK2-positive breast cancer, the adjusted hazard ratio associated with ER-positive status was 0.88 (95 % CI 0.48-1.62). Among women with an ER-positive breast cancer, the adjusted hazard ratio associated with a CHEK2 mutation was 1.31 (95 % CI 0.97-1.77). The survival of women with breast cancer and a CHEK2 mutation is similar to that of patients without a CHEK2 mutation.

Clinical characteristics of breast cancer in patients with an NBS1 mutation.

To identify characteristic features of breast cancers associated with an NBS1 mutation. To estimate and to compare 10-year survival rates for patients with early-onset breast cancer, with and without an NBS1 mutation. 4,566 women with stage I to stage III breast cancer, diagnosed at or below age 50, were tested for a founder mutation in the NBS1 gene. Information on tumor characteristics and on treatments received was retrieved from medical records. Dates of death were obtained from the Poland vital statistics registry. Survival curves for the mutation-positive and negative sub-cohorts were generated and were compared and the effect of an NBS1 mutation on survival was determined using the Cox proportional hazards model. 4566 patients were enrolled in the study, of whom 53 (1.2 %) carried a NBS1 mutation. Mutation carriers were similar to non-carriers in terms of tumor receptor status, grade, and lymph node status. The 10-year survival for NBS1 mutation carriers was 81.2 % (95 % CI 70.1-94.1 %) and for non-carriers was 79.4 % (95 % CI 78.0-80.9 %). The presence of an NBS1 mutation is not associated with prognosis (HR = 1.21; 95 % 0.67-2.19). The survival of women with breast cancer and a NBS1 mutation is similar to that of patients without a NBS1 mutation.

Are two-centimeter breast cancers large or small?

BACKGROUND: Node-negative breast cancers from 2 cm to 5 cm in size are classified as stage ii, and smaller cancers, as stage i. We sought to determine if the prognosis of women with a breast cancer exactly 2 cm in size more closely resembles that of women with a stage i or a stage ii breast cancer. METHODS: Using a cohort of 4265 young women with breast cancer, we compared the 10-year breast cancer mortality rates for women who had a tumour 0.1-1.9 cm, exactly 2.0 cm, and 2.1-2.9 cm. RESULTS: In the first 3 years after diagnosis, the survival pattern of women with a 2.0-cm breast cancer was nearly identical to that of women with a larger cancer (2.1-3.0 cm). From year 3 to year 10, the relative survival of women with a 2.0-cm breast cancer was improved and nearly identical to that of women with a smaller cancer. The 10-year survival rate was 89.3% for women with tumours less than 20 mm, 86.1% for women with tumours equal to 20 mm, and 81.2% for women with 21-mm to 29-mm tumours. CONCLUSIONS: For young women with small breast cancers, the relative mortality from breast cancer is dynamic with increasing tumour size and varies with time from diagnosis.

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.

Association of PHB 1630 C>T and MTHFR 677 C>T polymorphisms with breast and ovarian cancer risk in BRCA1/2 mutation carriers: results from a multicenter study.

BACKGROUND: The variable penetrance of breast cancer in BRCA1/2 mutation carriers suggests that other genetic or environmental factors modify breast cancer risk. Two genes of special interest are prohibitin (PHB) and methylene-tetrahydrofolate reductase (MTHFR), both of which are important either directly or indirectly in maintaining genomic integrity. METHODS: To evaluate the potential role of genetic variants within PHB and MTHFR in breast and ovarian cancer risk, 4102 BRCA1 and 2093 BRCA2 mutation carriers, and 6211 BRCA1 and 2902 BRCA2 carriers from the Consortium of Investigators of Modifiers of BRCA1 and BRCA2 (CIMBA) were genotyped for the PHB 1630 C>T (rs6917) polymorphism and the MTHFR 677 C>T (rs1801133) polymorphism, respectively. RESULTS: There was no evidence of association between the PHB 1630 C>T and MTHFR 677 C>T polymorphisms with either disease for BRCA1 or BRCA2 mutation carriers when breast and ovarian cancer associations were evaluated separately. Analysis that evaluated associations for breast and ovarian cancer simultaneously showed some evidence that BRCA1 mutation carriers who had the rare homozygote genotype (TT) of the PHB 1630 C>T polymorphism were at increased risk of both breast and ovarian cancer (HR 1.50, 95%CI 1.10-2.04 and HR 2.16, 95%CI 1.24-3.76, respectively). However, there was no evidence of association under a multiplicative model for the effect of each minor allele. CONCLUSION: The PHB 1630TT genotype may modify breast and ovarian cancer risks in BRCA1 mutation carriers. This association need to be evaluated in larger series of BRCA1 mutation carriers.

Vitamin D receptor variants and the malignant melanoma risk: a population-based study.

BACKGROUND: There is continuing interest in identifying low-penetrance genes which are associated with an increased susceptibility to common types of cancer, including malignant melanoma. METHODS: We sought to examine the association between four VDR common variants (rs1544410, rs731236, rs10735810, rs4516035) and the risk of melanoma in the Polish population. We also determined the prevalence of compound carriers of VDR and known MM genetic risk factors MC1R and CDKN2A (A148T) variants. We examined 763 unselected melanoma cases, 763 healthy adults matched for sex and age with the melanoma cases and 777 newborns. RESULTS: None of the VDR variants alone or as compound carriers of two or more of the VDR genotypes were associated with MM risk. There were no major differences between the prevalences of the examined variants among patients with MM on UV-exposed and UV-non exposed skin areas, as well as among early-onset and late-onset cases. We found no association between VDR and MC1R or between VDR and CDKN2A common variants. A statistically significant over-representation of one VDR haplotype: rs731236_A+rs1544410_T (OR=3.2, p=0.02) was detected. Linkage disequilibrium of rs1544410 and rs731236 was confirmed. CONCLUSION: To answer the question, whether VDR can be regarded as melanoma susceptibility gene, additional, large multi-center association studies have to be performed.

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.