BACKGROUND: The DNA released into the bloodstream by malignant tumours· called circulating tumour DNA (ctDNA), is often a small fraction of total cell-free DNA shed predominantly by hematopoietic cells and is therefore challenging to detect. Understanding the biological properties of ctDNA is key to the investigation of its clinical relevance as a non-invasive marker for cancer detection and monitoring. METHODS: We selected 40 plasma DNA samples of pancreatic cancer cases previously reported to carry a KRAS mutation at the 'hotspot' codon 12 and re-screened the cell-free DNA using a 4-size amplicons strategy (57 bp, 79 bp, 167 bp and 218 bp) combined with ultra-deep sequencing in order to investigate whether amplicon lengths could impact on the capacity of detection of ctDNA, which in turn could provide inference of ctDNA and non-malignant cell-free DNA size distribution. FINDINGS: Higher KRAS amplicon size (167 bp and 218 bp) was associated with lower detectable cell-free DNA mutant allelic fractions (p < 0·0001), with up to 4·6-fold (95% CI: 2·6-8·1) difference on average when comparing the 218bp- and the 57bp-amplicons. The proportion of cases with detectable KRAS mutations was also hampered with increased amplicon lengths, with only half of the cases having detectable ctDNA using the 218 bp assay relative to those detected with amplicons less than 80 bp. INTERPRETATION: Tumour-derived mutations are carried by shorter cell-free DNA fragments than fragments of wild-type allele. Targeting short amplicons increases the sensitivity of cell-free DNA assays for pancreatic cancer and should be taken into account for optimized assay design and for evaluating their clinical performance. FUNDING: IARC; MH CZ - DRO; MH SK; exchange program between IARC and Sao Paulo medical Sciences; French Cancer League.

• Klíčová slova
• Cell-free DNA, KRAS mutations, Pancreatic cancer detection, Plasma,
• MeSH
• alely MeSH
• chronická pankreatitida krev   diagnóza   genetika   patologie   MeSH
• cirkulující nádorová DNA krev   genetika   MeSH
• exprese genu MeSH
• frekvence genu MeSH
• kodon MeSH
• lidé MeSH
• mutace MeSH
• nádorové biomarkery krev   genetika   MeSH
• nádory slinivky břišní krev   diagnóza   genetika   patologie   MeSH
• protoonkogenní proteiny p21(ras) krev   genetika   MeSH
• sekvence nukleotidů MeSH
• senzitivita a specificita MeSH
• studie případů a kontrol MeSH
• výpočetní biologie MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• Názvy látek
• cirkulující nádorová DNA MeSH
• kodon MeSH
• KRAS protein, human MeSH Prohlížeč
• nádorové biomarkery MeSH
• protoonkogenní proteiny p21(ras) MeSH

The utility of KRAS mutations in plasma circulating cell-free DNA (cfDNA) samples as non-invasive biomarkers for the detection of pancreatic cancer has never been evaluated in a large case-control series. We applied a KRAS amplicon-based deep sequencing strategy combined with analytical pipeline specifically designed for the detection of low-abundance mutations to screen plasma samples of 437 pancreatic cancer cases, 141 chronic pancreatitis subjects, and 394 healthy controls. We detected mutations in 21.1% (N=92) of cases, of whom 82 (89.1%) carried at least one mutation at hotspot codons 12, 13 or 61, with mutant allelic fractions from 0.08% to 79%. Advanced stages were associated with an increased proportion of detection, with KRAS cfDNA mutations detected in 10.3%, 17,5% and 33.3% of cases with local, regional and systemic stages, respectively. We also detected KRAS cfDNA mutations in 3.7% (N=14) of healthy controls and in 4.3% (N=6) of subjects with chronic pancreatitis, but at significantly lower allelic fractions than in cases. Combining cfDNA KRAS mutations and CA19-9 plasma levels on a limited set of case-control samples did not improve the overall performance of the biomarkers as compared to CA19-9 alone. Whether the limited sensitivity and specificity observed in our series of KRAS mutations in plasma cfDNA as biomarkers for pancreatic cancer detection are attributable to methodological limitations or to the biology of cfDNA should be further assessed in large case-control series.

• Klíčová slova
• KRAS mutations, cell-free DNA, pancreatic cancer detection, plasma,
• MeSH
• antigen CA-19-9 krev   MeSH
• cirkulující nádorová DNA krev   genetika   MeSH
• duktální karcinom slinivky břišní krev   genetika   patologie   MeSH
• fenotyp MeSH
• frekvence genu MeSH
• genetická predispozice k nemoci MeSH
• lidé středního věku MeSH
• lidé MeSH
• mutace * MeSH
• mutační analýza DNA MeSH
• nádorové biomarkery krev   genetika   MeSH
• nádory slinivky břišní krev   genetika   patologie   MeSH
• pilotní projekty MeSH
• prediktivní hodnota testů MeSH
• protoonkogenní proteiny p21(ras) krev   genetika   MeSH
• reprodukovatelnost výsledků MeSH
• senioři MeSH
• staging nádorů MeSH
• studie případů a kontrol MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• validační studie MeSH
• Geografické názvy
• Česká republika MeSH
• Slovenská republika MeSH
• Názvy látek
• antigen CA-19-9 MeSH
• cirkulující nádorová DNA MeSH
• KRAS protein, human MeSH Prohlížeč
• nádorové biomarkery MeSH
• protoonkogenní proteiny p21(ras) MeSH

OBJECTIVES: We aimed to evaluate the relation between menstrual and reproductive factors, exogenous hormones, and risk of pancreatic cancer (PC). METHODS: Eleven case-control studies within the International Pancreatic Cancer Case-control Consortium took part in the present study, including in total 2838 case and 4748 control women. Pooled estimates of odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated using a 2-step logistic regression model and adjusting for relevant covariates. RESULTS: An inverse OR was observed in women who reported having had hysterectomy (ORyesvs.no, 0.78; 95% CI, 0.67-0.91), remaining significant in postmenopausal women and never-smoking women, adjusted for potential PC confounders. A mutually adjusted model with the joint effect for hormone replacement therapy (HRT) and hysterectomy showed significant inverse associations with PC in women who reported having had hysterectomy with HRT use (OR, 0.64; 95% CI, 0.48-0.84). CONCLUSIONS: Our large pooled analysis suggests that women who have had a hysterectomy may have reduced risk of PC. However, we cannot rule out that the reduced risk could be due to factors or indications for having had a hysterectomy. Further investigation of risk according to HRT use and reason for hysterectomy may be necessary.

• MeSH
• lidé MeSH
• logistické modely MeSH
• nádory slinivky břišní * MeSH
• odds ratio MeSH
• rizikové faktory MeSH
• studie případů a kontrol MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Pancreatic cancer is the fourth leading cause of cancer death in the developed world. Both inherited high-penetrance mutations in BRCA2 (ref. 2), ATM, PALB2 (ref. 4), BRCA1 (ref. 5), STK11 (ref. 6), CDKN2A and mismatch-repair genes and low-penetrance loci are associated with increased risk. To identify new risk loci, we performed a genome-wide association study on 9,925 pancreatic cancer cases and 11,569 controls, including 4,164 newly genotyped cases and 3,792 controls in 9 studies from North America, Central Europe and Australia. We identified three newly associated regions: 17q25.1 (LINC00673, rs11655237, odds ratio (OR) = 1.26, 95% confidence interval (CI) = 1.19-1.34, P = 1.42 × 10(-14)), 7p13 (SUGCT, rs17688601, OR = 0.88, 95% CI = 0.84-0.92, P = 1.41 × 10(-8)) and 3q29 (TP63, rs9854771, OR = 0.89, 95% CI = 0.85-0.93, P = 2.35 × 10(-8)). We detected significant association at 2p13.3 (ETAA1, rs1486134, OR = 1.14, 95% CI = 1.09-1.19, P = 3.36 × 10(-9)), a region with previous suggestive evidence in Han Chinese. We replicated previously reported associations at 9q34.2 (ABO), 13q22.1 (KLF5), 5p15.33 (TERT and CLPTM1), 13q12.2 (PDX1), 1q32.1 (NR5A2), 7q32.3 (LINC-PINT), 16q23.1 (BCAR1) and 22q12.1 (ZNRF3). Our study identifies new loci associated with pancreatic cancer risk.

• MeSH
• celogenomová asociační studie metody   MeSH
• frekvence genu MeSH
• genetická predispozice k nemoci genetika   MeSH
• genetické lokusy genetika   MeSH
• genotyp MeSH
• jednonukleotidový polymorfismus * MeSH
• lidé středního věku MeSH
• lidé MeSH
• lidské chromozomy, pár 17 genetika   MeSH
• lidské chromozomy, pár 2 genetika   MeSH
• lidské chromozomy, pár 3 genetika   MeSH
• lidské chromozomy, pár 7 genetika   MeSH
• nádory slinivky břišní genetika   MeSH
• rizikové faktory MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH
• Geografické názvy
• Austrálie MeSH
• Evropa MeSH
• Severní Amerika MeSH

BACKGROUND: Type 2 diabetes mellitus has been associated with an excess risk of pancreatic cancer, but the magnitude of the risk and the time-risk relationship are unclear, and there is limited information on the role of antidiabetic medications. PATIENTS AND METHODS: We analyzed individual-level data from 15 case-control studies within the Pancreatic Cancer Case-Control Consortium, including 8305 cases and 13 987 controls. Pooled odds ratios (ORs) were estimated from multiple logistic regression models, adjusted for relevant covariates. RESULTS: Overall, 1155 (15%) cases and 1087 (8%) controls reported a diagnosis of diabetes 2 or more years before cancer diagnosis (or interview, for controls), corresponding to an OR of 1.90 (95% confidence interval, CI, 1.72-2.09). Consistent risk estimates were observed across strata of selected covariates, including body mass index and tobacco smoking. Pancreatic cancer risk decreased with duration of diabetes, but a significant excess risk was still evident 20 or more years after diabetes diagnosis (OR 1.30, 95% CI 1.03-1.63). Among diabetics, long duration of oral antidiabetic use was associated with a decreased pancreatic cancer risk (OR 0.31, 95% CI 0.14-0.69, for ≥15 years). Conversely, insulin use was associated with a pancreatic cancer risk in the short term (OR 5.60, 95% CI 3.75-8.35, for <5 years), but not for longer duration of use (OR 0.95, 95% CI 0.53-1.70, for ≥15 years). CONCLUSION: This study provides the most definitive quantification to date of an excess risk of pancreatic cancer among diabetics. It also shows that a 30% excess risk persists for more than two decades after diabetes diagnosis, thus supporting a causal role of diabetes in pancreatic cancer. Oral antidiabetics may decrease the risk of pancreatic cancer, whereas insulin showed an inconsistent duration-risk relationship.

• Klíčová slova
• case–control study, diabetes, insulin, oral antidiabetics, pancreatic cancer, pooled analysis,
• MeSH
• diabetes mellitus 2. typu komplikace   farmakoterapie   epidemiologie   patologie   MeSH
• dospělí MeSH
• hypoglykemika terapeutické užití   MeSH
• inzulin MeSH
• kouření MeSH
• lidé středního věku MeSH
• lidé MeSH
• logistické modely MeSH
• nádory slinivky břišní farmakoterapie   epidemiologie   etiologie   patologie   MeSH
• rizikové faktory MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• hypoglykemika MeSH
• inzulin MeSH