Molecular signature of cell cycle exit induced in human T lymphoblasts by IL-2 withdrawal.

BACKGROUND: The molecular mechanisms of cell cycle exit are poorly understood. Studies on lymphocytes at cell cycle exit after growth factor deprivation have predominantly focused on the initiation of apoptosis. We aimed to study gene expression profile of primary and immortalised IL-2-dependent human T cells forced to exit the cell cycle by growth factor withdrawal, before apoptosis could be evidenced. RESULTS: By the Affymetrix microarrays HG-U133 2.0 Plus, 53 genes were distinguished as differentially expressed before and soon after IL-2 deprivation. Among those, PIM1, BCL2, IL-8, HBEGF, DUSP6, OSM, CISH, SOCS2, SOCS3, LIF and IL13 were down-regulated and RPS24, SQSTM1, TMEM1, LRRC8D, ECOP, YY1AP1, C1orf63, ASAH1, SLC25A46 and MIA3 were up-regulated. Genes linked to transcription, cell cycle, cell growth, proliferation and differentiation, cell adhesion, and immune functions were found to be overrepresented within the set of the differentially expressed genes. CONCLUSION: Cell cycle exit of the growth factor-deprived T lymphocytes is characterised by a signature of differentially expressed genes. A coordinate repression of a set of genes known to be induced during T cell activation is observed. However, growth arrest following exit from the cell cycle is actively controlled by several up-regulated genes that enforce the non-dividing state. The identification of genes involved in cell cycle exit and quiescence provides new hints for further studies on the molecular mechanisms regulating the non-dividing state of a cell, the mechanisms closely related to cancer development and to many biological processes.

Spontaneously immortalized T lymphocytes from Nijmegen Breakage Syndrome patients display phenotypes typical for lymphoma cells.

We found that the peripheral T lymphocytes from four of eight patients with the lymphoma predisposing Nijmegen Breakage Syndrome (NBS) acquired an unlimited growth potential following in vitro mitogen stimulation and subsequent interleukin-2-dependent propagation. The immortal T cell lines revealed morphological and other features typical for anaplastic large cell lymphoma (ALCL). In addition, multiple copies of ALK, but with no ALK gene rearrangements were found in a subpopulation of cells of one of the immortalized lines. These cell lines may be useful for the in vitro elucidation of mechanisms involved in the development of ALCL.

Nine years of irrigation cause vegetation and fine root shifts in a water-limited pine forest.

Scots pines (Pinus sylvestris L.) in the inner-Alpine dry valleys of Switzerland have suffered from increased mortality during the past decades, which has been caused by longer and more frequent dry periods. In addition, a proceeding replacement of Scots pines by pubescent oaks (Quercus pubescens Willd.) has been observed. In 2003, an irrigation experiment was performed to track changes by reducing drought pressure on the natural pine forest. After nine years of irrigation, we observed major adaptations in the vegetation and shifts in Scots pine fine root abundance and structure. Irrigation permitted new plant species to assemble and promote canopy closure with a subsequent loss of herb and moss coverage. Fine root dry weight increased under irrigation and fine roots had a tendency to elongate. Structural composition of fine roots remained unaffected by irrigation, expressing preserved proportions of cellulose, lignin and phenolic substances. A shift to a more negative δ13C signal in the fine root C indicates an increased photosynthetic activity in irrigated pine trees. Using radiocarbon (14C) measurement, a reduced mean age of the fine roots in irrigated plots was revealed. The reason for this is either an increase in newly produced fine roots, supported by the increase in fine root biomass, or a reduced lifespan of fine roots which corresponds to an enhanced turnover rate. Overall, the responses belowground to irrigation are less conspicuous than the more rapid adaptations aboveground. Lagged and conservative adaptations of tree roots with decadal lifespans are challenging to detect, hence demanding for long-term surveys. Investigations concerning fine root turnover rate and degradation processes under a changing climate are crucial for a complete understanding of C cycling.

Driving forces behind the past and future emergence of personalized medicine.

Personalized medicine can be seen as a continuously developing approach to tailoring treatments according to the individual characteristics of a patient. In some way, medicine has always been personalized. During the last decade, however, scientific and technological progress have made truly personalized healthcare increasingly become reality. Today's personalized medicine involves targeted therapies and diagnostic tests. The development of targeted agents represents a major investment opportunity to pharmaceutical companies, which have been facing the need to diversify their business due to an increasingly challenging market place. By investing into the development of personalized therapies, pharmaceutical companies mitigate a major part of the risks posed by factors such as patent expiries or generic competition. Viewing upon personalized medicine from different perspectives points out the multi-causality of its emergence. Research efforts and business diversification have been two main driving forces; they do supplement each other, however, are not jointly exhaustive in explaining the emergence of this approach. Especially in the future, a number of further stakeholders will impact the evolution of personalized medicine.

Association of the BRCA1 promoter polymorphism rs11655505 with the risk of familial breast and/or ovarian cancer.

Germline mutations in the BRCA1 tumor suppressor gene predispose affected individuals to breast cancer; however, incomplete cancer penetrance and the presence of phenocopies in BRCA1 families also indicate genetic and environmental modifiers of breast cancer risk. In this study, we have tested the single nucleotide polymorphism rs1655505 of the BRCA1 promoter, as candidate for the modifier of breast cancer risk. The polymorphic variants were genotyped in BRCA1-negative (729), familial breast and/or ovarian cancer cases (FBOC), including cases with a reported maternal history (154), nonfamilal (sporadic) cases (600), hereditary breast/ovarian cases with BRCA1 mutations (190) and population controls (1,590) from Central Poland. An association with the risk of FBOC was observed for the minor (T) allele and (TT) genotype (T: p = 0.006, OR = 1.40, 95% CI = 1.10-1.79; TT: p = 0.001, OR = 2.23, 95% CI = 1.37-3.62) in female cases with a reported maternal history, specifically in women with the onset of disease after 50 years of age (T: p = 0.004, OR = 1.77, 95% CI = 1.20-2.62; TT: p = 0.001, OR = 3.7, 95% CI = 1.62-8.46). The presented evidence suggests a need to conduct larger studies on the association between genetic variations at the BRCA1 promoter and the breast cancer risk, according to maternal/paternal lineage.

LGR4 and LGR6 are differentially expressed and of putative tumor biological significance in gastric carcinoma.

Gastric cancer (GC) is one of the most common causes of cancer-related deaths worldwide. We investigated the differential expression and putative tumor biological significance of five G-protein-coupled receptors (GPCRs) in GC, i.e., LGR4, LGR6, GPR34, GPR160, and GPR171. Based on our previous microarray analyses, we identified five candidate genes in human GC samples. Real-time RT-PCR was carried out to validate their expression in malignant and non-malignant tissues on an independent collective comprising 32 GC patients with and without lymph node metastases. Selected protein targets LGR4 and LGR6 were further validated on paraffin-embedded sections of ten intestinal and ten poorly cohesive (diffuse)-type GCs and their corresponding non-malignant tissue using immunohistochemistry. Additionally, the putative tumor biological significance of LGR4 and LGR6 was studied using tissue microarrays obtained from a cohort of 481 GC patients. On transcriptional level, GPR34, GPR160, and GPR171 were not differentially expressed in GC compared with non-neoplastic mucosa. LGR4 and LGR6 were up-regulated on transcriptional (real-time RT-PCR) and translational (immunohistochemistry) levels in GC. Furthermore, in tissue microarray analysis, LGR6 expression was significantly associated with local tumor growth (T-category; p = 0.04) and correlated with patient survival. LGR4 expression was significantly correlated with nodal spread (N-category; p = 0.025). Our systematic analysis indicates that LGR4 and LGR6 may play a role in GC biology. Future studies will have to demonstrate whether these are also putative diagnostic, prognostic, and/or therapeutic targets for GC.

Limited significance of family history for presence of BRCA1 gene mutation in Polish breast and ovarian cancer cases.

It is estimated that about 5-10% of ovarian and 2-5% of all breast cancer patients are carriers of a germline BRCA1 or BRCA2 gene mutation. Most families with detected BRCA1 or BRCA2 gene mutation are qualified for molecular testing on the basis of family history of breast or ovarian cancers. The purpose of our study was to establish the frequency of positive family history of cancer in a series of Polish consecutive breast and ovarian cancer patients in two groups, with and without the BRCA1 gene mutations. We analysed the prevalence of four of the most common BRCA1 mutations: 5382insC (c.5266dupC), 300T>G (p.181T>G), 185delAG (c.68_69delAG) and 3819del5 (c.3700_3704del5). The patient group consisted of 1,845 consecutive female breast and 363 ovarian cancer cases. 19 out of 37 (51%) of BRCA1-positive ovarian cancer patients and 21 out of 55 (39%) BRCA1-positive breast cancer had negative family history of breast and/or ovarian cancer among first- and second-degree relatives. In ovarian cancer patients, negative family history was more frequent in those with 300T>G BRCA1 gene mutation than in 5382insC carriers. This finding indicates the necessity of searching for 300T>G mutation in families with a single diagnosis of ovarian cancer in family. The high frequency of mutations detected in breast cancer patients lacking obvious family history shows that breast cancer patients should be qualified for genetic testing on the basis of wide clinical and pathological criteria.

Prevalence of the most frequent BRCA1 mutations in Polish population.

The purpose of our study was to establish the frequency and distribution of the four most common BRCA1 mutations in Polish general population and in a series of breast cancer patients. Analysis of the population frequency of 5382insC (c.5266dupC), 300T >G (p.181T >G), 185delAG (c.68_69delAG) and 3819del5 (c.3700_3704del5) mutations of the BRCA1 gene were performed on a group of respectively 16,849, 13,462, 12,485 and 3923 anonymous samples collected at birth in seven Polish provinces. The patient group consisted of 1845 consecutive female breast cancer cases. The most frequent BRCA1 mutation in the general population was 5382insC found in 29 out of 16,849 samples (0.17%). 300T >G and 3819del5 mutations were found in respectively 11 of 13,462 (0.08%) and four of 3923 (0.1%) samples. The population prevalence for combined Polish founder 5382insC and 300T >G mutations was 0.25% (1/400). The frequencies of 5382insC and 300T >G carriers among consecutive breast cancer cases were, respectively, 1.9% (35/1845) and 1.2% (18/1486). Comparing these data with the population frequency, we calculated the relative risk of breast cancer for 5382insC mutation at OR = 17 and for 300T >G mutation at OR = 26. Our results, based on large population studies, show high frequencies of founder 5382insC and 300T >G BRCA1 mutations in Polish general population. Carriage of one of these mutations is connected with a very high relative risk of breast cancer.

The frequency of selected polymorphic variants of the RET gene in patients with medullary thyroid carcinoma and in the general population of central Poland.

The object of this work was to compare the frequency of three polymorphic changes in the RET proto-oncogene: L769L, S836S, and S904S in patients with medullary thyroid carcinoma (MTC; n = 246) and in the general population (n = 420 for single-nucleotide polymorphism [SNP] L769L and S904S; n = 411 for SNP 836). We tried to investigate how the harbored SNPs affect the age at onset of sporadic medullary thyroid carcinoma (sMTC) and MTC in carriers of known pathogenic mutations at codons 634 and 791 of the RET gene. A statistically significant difference was found in the frequency of the heterozygous change L769L in patients with sMTC (48.3%) and in unaffected individuals (39.5%). The presence of the polymorphic change L769L in the RET gene predisposes to the development of sMTC and also lowers the age of onset of MTC in carriers of the homozygous polymorphic variant L769L. The presence of this polymorphic change in MTC patients carrying, at the same time, the RET codon 634 mutation lowers the age of onset of MTC in this group.

First Polish Cowden syndrome patient with confirmed PTEN gene mutation.

Cowden syndrome is a rare hereditary disease. Incidence of the disease is conditioned by occurrence of mutations in the PTEN gene. The disease has a frequency of 1/120,000 newborn and it predisposes to the occurrence of hamartoma polyps in the gastrointestinal tract, skin tumours, as well as tumours of the breast, ovary and thyroid. Here we describe the case of a Polish patient diagnosed with Cowden syndrome with an identified mutation in the PTEN gene. The disease course of the patient is described and discussed along with other cases of carriers of substitution 68T>A in the PTEN gene.

Increased risk of gastrointestinal lymphoma in carriers of the 657del5 NBS1 gene mutation.

The NBS1 gene mutation, 657del5, frequent in the Slavic populations of Central Europe, is found in most patients with Nijmegen breakage syndrome (NBS), a recessive autosomal disorder with a very high incidence of non-Hodgkin lymphoma (NHL). We have previously described 2 heterozygous 657del5 mutation carriers among 42 adult NHL probands from Central Poland. Here we report 6 additional carriers of the 657del5 mutation and 2 carriers of the pathogenic NBS1 R215W mutation, among 186 other NHL patients also from Central Poland. The 657del5 carrier frequency in the pooled group of these 228 patients was significantly higher than in population controls (OR 5.85, 95% CI: 2.29-15.00, p = 0.0001). Interestingly, 4 of these carriers were found among 37 patients with gastrointestinal lymphoma (OR 19.52, 95% CI: 5.82-65.42, p = 0.0002). These findings imply that heterozygous NBS1 germline mutations may contribute significantly to the overall incidence of NHL, especially of the gastrointestinal tract, in Central Europe.

Germline mutations 657del5 of the NBS1 gene contribute significantly to the incidence of breast cancer in Central Poland.

Recent studies have demonstrated that heterozygous carriers of the NBS1 657del5 mutation have an increased risk for familial and bilateral breast cancer, but similar studies in consecutive breast cancer patients were inconclusive. Here, in a study of 562 nonselected breast cancer patients from Central Poland, we found 11 (1.96%) 657del5 mutation carriers vs. 3.47 expected (OR 3.21, 95%CI: 1.36-7.61, p = 0.0107) and only 9 (1.6%) carriers of the 5382insC mutation of the BRCA1 gene, most frequently found among breast cancer patients in Poland. No carriers of R215W, another pathogenic mutation of the NBS1 gene, were found in the present study. All carriers of the 657del5 mutation had sporadic breast tumors while 5 of 9 5382insC carriers had a family history of breast/ovarian cancer or bilateral breast carcinoma. In the pooled group of patients from the present and our previous study, carried out also in patients from Central Poland, we obtained the following risk estimates (OR) for 657del5 carriers, as related to the age at breast cancer diagnosis: < 40 years: 8.36; (95%CI: 2.57-27.27) p = 0.0003; < 50 years: 4.27 (95%CI: 1.67-10.89) p = 0.003; > or = 50 years: 2.40 (95%CI: 0.91-6.35) p = 0.1250; all ages: 3.13 (95% CI: 1.40-7.00) p = 0.0066. These findings demonstrate conclusively that NBS1 657del5 mutation carriers have a significantly, though moderately increased, age-related risk of breast cancer, and imply that in populations with a high 657del5 carrier frequency this mutation may contribute substantially to the overall incidence of breast cancer, particularly in younger age groups.

Pretreatment serum levels of cytokines and cytokine receptors in patients with non-small cell lung cancer, and correlations with clinicopathological features and prognosis. M-CSF - an independent prognostic factor.

OBJECTIVES: Cytokines are potential new serum markers, especially desirable for malignancies with poor prognosis like non-small cell lung cancer (NSCLC). METHODS: Cytokines, tumor necrosis factor alpha (TNFalpha), interleukin (IL)-6 and IL-8, soluble TNF (sTNF) RI, sTNF RII, soluble IL-2 receptor-alpha, IL-1 receptor antagonist (IL-1ra), IL-10, vascular endothelial growth factor, basic fibroblast growth factor, and macrophage (M-CSF) and granulocyte colony-stimulating factor, as well as tumor markers - carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC) and CYFRA 21.1 - were assessed in the sera of 103 untreated NSCLC patients, and these cytokines and tumor markers were referred to clinical parameters of the disease and to the overall survival of patients evaluated during a 6-year follow-up. RESULTS: Most of the factors analyzed were found to be elevated in the sera of NSCLC patients, and increases in IL-6, IL-8 and sTNF RI were noted in the greatest proportion of stage I patients. Most cytokine/cytokine receptor levels revealed higher sensitivity than the standard tumor markers; IL-6 and IL-1ra levels were significantly different in patients with squamous cell versus adenocarcinoma; IL-6 and IL-10 were related to the tumor size, while IL-6 and M-CSF levels significantly increased with disease progression. A significant prognostic value of pretreatment serum M-CSF and CEA levels in NSCLC patients has been shown, but only M-CSF proved to be an independent prognostic factor. CONCLUSIONS: Increased pretreatment serum M-CSF level is a significant independent predictor of poor survival in patients with NSCLC.

Cytokine and cytokine receptor serum levels in adult bone sarcoma patients: correlations with local tumor extent and prognosis.

BACKGROUND AND OBJECTIVES: We analyzed the correlations between pretreatment serum levels of 11 cytokines and soluble cytokine receptors (interleukin 6 (IL-6); interleukin 8 (IL-8); interleukin 10 (IL-10); vascular endothelial growth factor (VEGF); basic fibroblast growth factor (bFGF); macrophage colony-stimulating factor (M-CSF); granulocyte colony-stimulating factor (G-CSF); interleukin 1 receptor antagonist (IL-1ra); sIL-2Ralpha; tumor necrosis factor receptor I (TNF RI), and TNF RII) with clinico-pathological features and survival of patients with bone sarcomas. METHODS: Altogether, 72 patients with bone sarcomas without distant metastases before treatment (26 osteosarcomas-36%, 23 chondrosarcomas-32%, 13 Ewing's sarcomas/PNET-18%, 10 giant-cell tumors-14%), 22 patients with benign non-inflammatory bone tumors and 50 age-matched healthy controls were included into this prospective study. RESULTS: Median serum levels of 9/11 cytokines, with the exception of sIL-2Ralpha and G-CSF, were significantly higher in sarcoma patients than in controls. Median serum levels of IL-6, IL-8, IL-1ra, TNF RI, and M-CSF were significantly higher in patients with bone sarcoma as compared to patients with benign bone tumors. In 45.9% of sarcoma patients, six or more cytokines and cytokine receptors, including those that are involved in bone destruction (e.g., IL-6 and IL-8) and bone formation (e.g., IL-1ra and TNFRI and TNFRII), were elevated in parallel. Serum levels of IL-6, IL-8, TNF RI, TNF RII, and VEGF correlated significantly with tumor size (<10 cm vs. >or=10 cm in diameter) and serum levels of IL-6, IL-8, TNF RI, and IL-1ra correlated significantly with local tumor extent (E2/4 vs. E5/6 according to the classification proposed by Spanier et al. 46). Moreover, serum levels of IL-1ra and IL-6 were significantly higher in patients with small tumors (<5 cm in diameter) infiltrating structures adjacent to the periosteum (E5/6) than in large tumors (>10 cm in diameter) but confined to the bone and periosteum (E < 4). The lowest median serum levels of 8/11 cytokines/cytokine receptors were found in patients with giant-cell tumors. In an univariate analysis, increased serum levels of IL-1ra, IL-6, IL-8, IL-10, sIL-2Ralpha, M-CSF, TNF RI, and TNF RII, the number of cytokines elevated, higher tumor grade, larger tumor size, greater local extent (E) and patients' age >35 years correlated with poor overall survival (OS) (P < 0.05). Similarly, high serum levels of IL-1ra, IL-6, TNF RI and TNF RII, tumor grade, tumor size, and tumor local extent (E) (P < 0.05) affected disease free survival (DFS) in univariate analysis. Multivariate analysis using Cox's proportional hazards model showed that high serum levels of IL-1ra (P = 0.039) and TNF RI (P = 0.048), the number of serum cytokines above normal cut-off values (0-1 vs. 2-5 vs. >or=6; P = 0.029), greater tumor local extent E (E2/4 vs. E5/6; P = 0.02) correlated significantly with shorter OS. Only E was found as an independent prognostic factor for DFS (P = 0.04). CONCLUSIONS: These findings indicate that cytokines and soluble cytokine receptors, both physiologically involved in bone destruction and bone formation, have an essential role in the progression of malignant bone tumors.

Sera of lung cancer patients affect the release of Th1, Th2 and monocyte-derived cytokines, and the expression of IL-2Ralpha by normal, stimulated mononuclear cells.

We have shown that the sera of lung cancer patients affect the response of ConA-stimulated normal peripheral blood mononuclear cells by decreasing the expression of IL-2Ralpha and inhibiting the release of IL-1beta and IL-2. A tendency to enhance the release of IL-6 was also observed. We conclude that an imbalance in the Th1/Th2 cytokine response, typical for cancer patients, may at least partly be related to soluble factors circulating in the patients' blood. We discuss a putative role of serum IL-10, IL-1ra, and soluble IL-2Ralpha in the effects observed.

Cytokine serum levels in soft tissue sarcoma patients: correlations with clinico-pathological features and prognosis.

We investigated the correlations between serum levels of selected proinflammatory, hematopoietic and angiogenic cytokines and soluble cytokine receptors with the clinico-pathological features and prognosis in soft tissue sarcoma patients. Serum levels of 9 cytokines (TNFalpha, IL-1ra, IL-6, IL-8, IL-10, M-CSF, G-CSF, VEGF, bFGF) and 4 free cytokine receptors (sIL-2R alpha, sIL-6R, TNFRI, TNFRII) were measured by means of an enzyme-linked immunoadsorbent assay kit in 156 soft tissue sarcoma patients before the treatment and in 50 healthy controls. Serum levels of 10 cytokines and cytokine receptors were also assayed during patients' follow-up after the treatment. Significantly elevated pretreatment serum levels of 11/13 cytokines and cytokine receptors were found in sarcoma patients, as compared to healthy controls. In 40.4% of patients 6 or more cytokines and cytokine receptors (most frequently: TNF RI, IL-6, IL-8) were elevated in parallel. Serum levels of IL-6, sIL-2R, VEGF, M-CSF and TNF RI correlated significantly with tumor size and serum levels of IL-8 and IL-6 were significantly higher in patients with Grade 2/3 vs. Grade 1 tumors. We did not observe any significant differences in cytokine serum levels between patients with primary and recurrent tumors and patients with and without distant metastases. Using univariate analysis, overall survival (OS) in all patients was affected by tumor size (<5 cm vs. 5-10 cm vs. >10 cm), tumor grade (G1 vs. G2/3), presence of metastases, pretreatment serum levels of 8 cytokines (IL-6, IL-8, IL-10, sIL-2R, TNF RI, TNF RII, M-CSF, VEGF) and the number of cytokines increased (0-1 vs. 2-5 vs. < or = 6). Elevated serum levels of IL-6, IL-8, IL-10 and sIL-2R alpha, high tumor grade and larger tumor size strongly correlated with shorter disease-free survival (DFS). Multivariate analysis identified G2/3 tumor grade (p = 0.001), the presence of metastases (p = 0.004), elevated IL-6 serum level (p = 0.02), elevated IL-8 serum level (p = 0.048) and the number of cytokine serum levels above upper cut-off values (p = 0.01) as the independent prognostic factors related to OS, and G2/3 tumor grade (p = 0.005) and increased IL-6 serum level (p = 0.035) as independent prognostic factors related to DFS. In a group of patients without metastases (M0) higher tumor grade, elevated serum level of IL-6 and TNF RII, and the number of elevated cytokine serum levels correlated independently with poor survival. We found a significant decrease of several cytokine serum levels in patients after treatment (IL-1ra, IL-6, IL-8, IL-10, TNF RII, M-CSF) [p < 0.05]. Persistently elevated serum level of IL-6 after the treatment has also shown negative prognostic significance for OS (univariate analysis). Serum levels of some proinflammatory, hematopoietic and angiogenic cytokines and cytokine receptors are elevated, frequently in parallel, in a large percentage of soft tissue sarcoma patients. Significant correlations of serum cytokine levels with tumor size and grade suggest that some of these cytokines may be directly or indirectly involved in the progression of soft tissue sarcomas. Serum assays of IL-6, IL-8 and TNF RII before or after the treatment may be useful in establishing soft tissue sarcoma patients prognosis.

Increased cancer risk of heterozygotes with NBS1 germline mutations in Poland.

It has been suggested based on familial data that Nijmegen breakage syndrome (NBS) heterozygotes have an increased risk of malignant tumors. We found 15 carriers of the 657del5 mutation and 8 carriers of the R215W molecular variant of the NBS1 gene among 1,289 consecutive patients from Central Poland with various cancers and only 10 and 4 such carriers, respectively, in 1,620 controls from this region. Most of the 657del5 mutation carriers were found among patients with melanoma (4/105), non-Hodgkin lymphoma (2/42) and breast cancer (4/224) and of the 234 patients with colorectal carcinoma 3 carried the 657del5 mutation and 3 others the R215W molecular variant. The frequencies of 657del5 mutation carriers among patients with melanoma and non-Hodgkin lymphoma and of R215W carriers in patients with colorectal cancer were significantly higher than in controls (p < 0.01, < 0.05 and < 0.05 respectively). The pooled frequencies of 657del5 and R215W mutations in all cancer patients were also significantly higher than in controls (p < 0.05). Two carriers of the 657del5 mutation had second primary tumors. Malignant tumors among parents and siblings of 657del5 mutation carriers (14/77) were twice more frequent than in population controls. Three carriers of this mutation (2 probands with melanoma) reported melanoma in relatives. These results suggest strongly that NBS1 heterozygosity may be associated with elevated risk of some cancers. Larger studies are needed to evaluate the impact of the high frequency of germline NBS1 mutations on the cancer burden in the Slav populations.