Summary Background Mutations in PALB2 predispose to breast cancer, but the effect on prognosis of carrying a PALB2 mutation has not been ascertained. We aimed to estimate the odds ratio for breast ...cancer in women with an inherited mutation in PALB2 and 10-year survival after breast cancer in patients who carry a PALB2 mutation. Methods Between 1996 and 2012, patients with invasive breast cancer were recruited prospectively from 18 hospitals in Poland and genotyped for two deleterious mutations in PALB2 (509_510delGA and 172_175delTTGT). A control group of 4702 women without cancer was recruited for comparison. The primary endpoint was death from any cause, as determined by medical records from the Polish Ministry of the Interior and Administration. In patients with breast cancer, 10-year survival of carriers of a PALB2 mutation was calculated and compared with that of non-carriers. Findings 17 900 women with breast cancer were invited to participate, of whom 12 529 were genotyped successfully. A PALB2 mutation was present in 116 (0·93%, 95% CI 0·76–1·09) of 12 529 patients and in ten (0·21%, 0·08–0·34) of 4702 controls (odds ratio 4·39, 95% CI 2·30–8·37; p<0·0001). 10-year survival for women with breast cancer and a PALB2 mutation was 48·0% (95% CI 36·5–63·2), compared with 74·7% (73·5–75·8) for patients with breast cancer without a mutation (adjusted hazard ratio for death 2·27, 95% CI 1·64–3·15; p<0·0001). Interpretation Women with a PALB2 mutation face an increased risk of breast cancer and might be at a higher risk of death from breast cancer compared with non-carriers. Increased surveillance should be offered to unaffected women who carry a PALB2 mutation. Funding Polish National Science Centre.
We developed an efficient approach to diagnostic copy number analysis of targeted gene panel or whole exome sequence (WES) data. Here we present CNV-Z as a new tool for detection of copy number ...variants (CNVs). Deletions and duplications of chromosomal regions are widely implicated in both genomic evolution and genetic disorders. However, calling CNVs from targeted or exome sequence data is challenging. In most cases, the copy number of a chromosomal region is estimated as the depth of reads mapping to a certain bin or sliding window divided by the expected number of reads derived from a set of reference samples. This approach will inevitably miss smaller CNVs on an irregular basis, and quite frequently results in a disturbing number of false positive CNVs.
We developed an alternative approach to detect CNVs based on deviation from expected read depth per position, instead of region. Cautiously used, the cohort of samples in the same run will do as a reference. With appropriate filtering, given high quality DNA and a set of suitable reference samples, CNV-Z detects CNVs ranging in length from one nucleotide to an entire chromosome, with few false positives. Performance is proved by benchmarking using both in-house targeted gene panel NGS data and a publicly available NGS dataset, both sets with multiplex ligation-dependent amplification probe (MLPA) validated CNVs. The outcome shows that CNV-Z detects single- and multi-exonic CNVs with high specificity and sensitivity using different kind of NGS data. On gene level, CNV-Z shows both excellent sensitivity and specificity. Compared to competing CNV callers, CNV-Z shows higher specificity and positive predictive value for detecting exonic CNVs.
The association of BRCA1/2 mutations with melanoma is not completely determined; the interpretation of variants of unknown significance is also problematic. To evaluate these issues we explored the ...molecular basis of melanoma risk by performing whole-exome sequencing on a cohort of 96 unrelated Polish early-onset melanoma patients and targeted sequencing of BRCA1/2 genes on additional 30 melanoma patients with familial aggregation of breast and other cancers. Sequencing was performed on peripheral blood. We evaluated MutationTaster, Polyphen2, SIFT, PROVEAN algorithms, analyzed segregation with cancer disease (in both families with identified BRCA2 variants) and in one family performed LOH (based on 2 primary tumors). We found neither pathogenic mutations nor variants of unknown significance within BRCA1. We identified two BRCA2 variants of unknown significance: c.9334G>A and c.4534 C>T. Disease allele frequency was evaluated by genotyping of 1230 consecutive melanoma cases, 5000 breast cancer patients, 3500 prostate cancers and 9900 controls. Both variants were found to be absent among unselected cancer patients and healthy controls. The MutationTaster, Polyphen2 and SIFT algorithms indicate that c.9334G>A is a damaging variant. Due to lack of tumour tissue LOH analysis could not be performed for this variant. The variant segregated with the disease. The c.4534 C>T variant did not segregate with disease, there was no LOH of the variant. The c.9334G>A variant, classified as a rare variant of unknown significance, on current evidence may predisposes to cancers of the breast, prostate and melanoma. Functional studies to describe how the DNA change affects the protein function and a large multi-center study to evaluate its penetrance are required.
There are twenty recurrent mutations in six breast-cancer-predisposing genes in Poland (BRCA1, BRCA2, CHEK2, PALB2, NBN, and RECQL). The frequencies of the twenty alleles have not been measured in a ...large series of early-onset breast cancer patients from Poland unselected for family history. We genotyped 2464 women with breast cancer diagnosed below age 41 years for twenty recurrent germline mutations in six genes, including BRCA1, BRCA2 CHEK2, PALB2, NBN, and RECQL. A mutation in one of the six genes was identified in 419 of the 2464 early-onset breast cancer cases (17%), including 22.4% of those cases diagnosed below age 31. The mutation frequency was 18.8% for familial breast cancer cases and 6% for non-familial cases. Among women with breast cancer below age 31, the mutation frequency was 23.6% for familial cases and 17.4% in non-familial cases. The majority of mutations (76.2%) were seen in BRCA1 and BRCA2. In Poland, a panel of twenty recurrent mutations in six genes can identify a genetic basis for a high percentage of early-onset cases and testing is recommended for all women with breast cancer at age 40 or below.
Mechanisms of acquired tumor drug resistance Aleksakhina, Svetlana N.; Kashyap, Aniruddh; Imyanitov, Evgeny N.
Biochimica et biophysica acta. Reviews on cancer,
12/2019, Letnik:
1872, Številka:
2
Journal Article
Recenzirano
Systemic therapy often results in the reduction of tumor size but rarely succeeds in eradicating all cancer cells. Drug efflux, persistence of cancer stem cells (CSCs), epithelial-mesenchymal ...transition (EMT) and down-regulation of apoptosis are the most known general causes of therapy failure. Tumor escape from targeted compounds often involves pathway-specific mechanisms, which result in the restoration of the affected signaling cascade. The acquisition of drug resistance is mediated by mutations, changes in gene expression, alternative splicing, post-translational protein modifications, etc. Development of resistance to therapy may not necessary involve the emergence of new tumor clones: multiple studies demonstrate that even chemonaive neoplasms already have a small population of cells, which are capable of surviving therapeutic pressure and facilitating the disease progression. Use of combinations of cancer drugs, sequential therapy, adaptive therapy and topical ablation of drug-resistant malignant lumps may help to prolong the time to treatment failure. Many studies on mechanisms of drug resistance rely on the use of cell cultures and animal models. The development of approaches that allow efficient monitoring of the evolution of tumor phenotype in clinical setting presents a challenge.
Familial pancreatic cancer describes families with at least two first-degree relatives with pancreatic cancer that do not fulfil the criteria of other inherited tumor syndromes with increased risks ...of pancreatic cancer. Although much has been learned regarding the aggregation of pancreatic cancer in some families, the genetic basis for this familial aggregation is poorly understood. This study evaluated the prevalence of 10 Polish founder mutations in four genes among individuals from families with diagnosed familial pancreatic cancer syndrome and assessed their possible association with the familial pancreatic cancer (FPC) risk in Poland.
In this study, 400 FPC individuals and 4,000 control subjects were genotyped for founder mutations in
(5382insC, 4153delA, C61G),
(1100delC, IVS2+1G>A, del5395, I157T),
(657del5), and
(509_510delGA, 172_175delTTGT) genes.
A statistically significant association was observed between the 172_175delTTGT mutation of the
gene and an increased risk of FPC syndrome (odds ratio OR, 10.05; p=0.048). In addition, an increased risk of cancer was observed in the FPC family members with a
mutation (OR, 6.72; p=0.006). Novel associations were found between the FPC family members with cancer and
mutations (OR, 2.26; p=0.008) with a noticeable contribution of the missense variant, I157T of
(OR, 2.17; p=0.026).
The founder mutations in the genes,
,
, and
, cause a small percentage of familial pancreatic cancer syndrome in the Polish population. Following confirmation in larger studies, these mutations can be added to the panel of genes to be tested in families with a diagnosis of FPC syndrome.
Germline mutations within melanoma susceptibility genes are present only in minority of melanoma patients and it is expected that additional genes will be discovered with next generation sequence ...technology and whole-exome sequencing (WES).
Herein we performed WES on a cohort of 96 unrelated Polish patients with melanoma diagnosed under the age of 40 years who all screened negative for the presence of CDKN2Avariants. A replication study using a set of 1,200 melanoma patient DNA samples and similarly large series of healthy controls was undertaken.
We selected 21 potentially deleterious variants in 20 genes (VRK1, MYCT1, DNAH14, CASC3, MS4A12, PRC1, WWOX, CARD6, EXO5, CASC3, CASP8AP2, STK33, SAMD11, CNDP2, CPNE1, EFCAB6, CABLES1, LEKR1, NUDT17, and RRP15), which were identified by WES and confirmed by Sanger sequencing for an association study. Evaluation of the allele distribution among carriers and their relatives in available family trios revealed that these variants were unlikely to account for many familial cases of melanoma. Replication study revealed no statistically significant differences between cases and controls.
Although most of the changes seemed to be neutral we could not exclude an association between variants in VRK1, CREB3L3, EXO5, and STK33 with melanoma risk.
Several moderate- and high-risk breast cancer susceptibility genes have been discovered, but more are likely to exist. To discover new breast cancer susceptibility genes, we used 2 populations (from ...Poland and Quebec, Canada) and applied whole-exome sequencing in a discovery phase (n = 195), followed by validation. We identified rare recurrent RECQL mutations in each population. In Quebec, 7 of 1,013 higher-risk breast cancer cases and 1 of 7,136 newborns carried the c.634C>T (p.Arg215*) variant (P = 0.00004). In Poland, 30 of 13,136 unselected breast cancer cases and 2 of 4,702 controls carried the c.1667_1667+3delAGTA (p.K555delinsMYKLIHYSFR) variant (P = 0.008). RECQL is implicated in resolving stalled DNA replication forks to prevent double-stranded DNA (dsDNA) breaks. This function is related to that of other known breast cancer susceptibility genes, many of which are involved in repairing dsDNA breaks. We conclude that RECQL is a breast cancer susceptibility gene.
In designing national strategies for genetic testing, it is important to define the full spectrum of pathogenic mutations in prostate cancer (PCa) susceptibility genes. To investigate the frequency ...of mutations in PCa susceptibility genes in Polish familial PCa cases and to estimate gene‐related PCa risks and probability of aggressive disease, we analyzed the coding regions of 14 genes by exome sequencing in 390 men with familial prostate cancer and 308 cancer‐free controls. We compared the mutation frequencies between PCa cases and controls. We also compared clinical characteristics of prostate cancers between mutation carriers and noncarriers. Of the 390 PCa cases, 76 men (19.5%) carried a mutation in BRCA1, BRCA2, NBN, ATM, CHEK2, HOXB13, MSH2 or MSH6 genes. No mutations were found in BRIP1, PTEN, TP53, MLH1, PMS2 and SPOP. Significant associations with familial PCa risk were observed for CHEK2, NBN, ATM, and HOXB13. High‐grade (Gleason 8‐10) tumors were seen in 56% of BRCA2, NBN or ATM carriers, compared to 21% of patients who tested negative for mutations in these genes (OR = 4.7, 95% CI 2.0‐10.7, P = .0003). In summary, approximately 20% of familial prostate cancer cases in Poland can be attributed to mutations in eight susceptibility genes. Carriers of mutations in BRCA2, NBN and ATM develop aggressive disease and may benefit from intensified screening and/or chemotherapy.
What's new?
Genetic susceptibility plays an important role in prostate cancer (PCa). In designing genetic‐testing strategies for PCa screening, it is important to define the full spectrum of pathogenic mutations that increase PCa risk. In this study, the authors found that approximately 20% of familial prostate cancer cases in Poland can be attributed to mutations in eight susceptibility genes. In addition, carriers of mutations in BRCA2, NBN and ATM are more likely to develop aggressive disease. These patients may benefit from intensified screening and/or chemotherapy.
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