Mutational Signature Analysis Reveals NTHL1 Deficiency to Cause a Multi-tumor Phenotype.

Biallelic germline mutations affecting NTHL1 predispose carriers to adenomatous polyposis and colorectal cancer, but the complete phenotype is unknown. We describe 29 individuals carrying biallelic germline NTHL1 mutations from 17 families, of which 26 developed one (n = 10) or multiple (n = 16) malignancies in 14 different tissues. An unexpected high breast cancer incidence was observed in female carriers (60%). Mutational signature analysis of 14 tumors from 7 organs revealed that NTHL1 deficiency underlies the main mutational process in all but one of the tumors (93%). These results reveal NTHL1 as a multi-tumor predisposition gene with a high lifetime risk for extracolonic cancers and a typical mutational signature observed across tumor types, which can assist in the recognition of this syndrome.

Ursodeoxycholic acid counteracts celecoxib in reduction of duodenal polyps in patients with familial adenomatous polyposis: a multicentre, randomized controlled trial.

BACKGROUND: Due to prophylactic colectomy, mortality in patients with familial adenomatous polyposis (FAP) has changed, with duodenal cancer currently being the main cause of death. Although celecoxib reduces duodenal polyp density in patients with FAP, its long-term use may increase the risk of cardiovascular events and alternatives need to be explored. Preclinical studies suggest that the combination of celecoxib with ursodeoxycholic acid (UDCA) is a potentially effective strategy. We performed a randomized, double-blind, placebo-controlled trial to investigate the effect of celecoxib and UDCA co-treatment on duodenal adenomatosis in patients with FAP. METHODS: Patients with FAP received celecoxib (400 mg twice daily) and UDCA (1000-2000 mg daily, ~20-30 mg/kg/day, n=19) or celecoxib and placebo (n=18) orally for 6 months. Primary outcome was drug efficacy, assessed by comparing duodenal polyp density at pre- and post-intervention by blinded review of endoscopic recordings. As secondary outcomes, cell proliferation, apoptosis, and COX-2 levels in normal duodenal mucosa were assessed by immunohistochemistry or real-time quantitative polymerase chain reaction. RESULTS: In intention-to-treat analysis, deceased polyp density was observed after celecoxib/placebo treatment (p=0.029), whereas increased polyp density was observed after celecoxib/UDCA treatment (p=0.014). The difference in change in duodenal polyp density was statistically significant between the groups (p=0.011). No changes in secondary outcomes were observed. Thirty patients (81%) reported one or more adverse events, 16 patients (84%, Common Toxicity Criteria for Adverse Events version 3.0 (CTCAE) grade 1-3) treated with celecoxib/UDCA and 14 patients (78%, CTCAE grade 1-2) treated with celecoxib/placebo. Nine patients (24%) discontinued intervention prematurely, 5 patients (26%) treated with celecoxib/UDCA and 4 patients (22%) treated with celecoxib/placebo. CONCLUSIONS: Celecoxib reduces duodenal polyp density in patients with FAP, and unexpectedly, high dose UDCA co-treatment counteracts this effect. The benefit of long term use of celecoxib for duodenal cancer prevention needs to be weighed against the (risk of) adverse events. TRIAL REGISTRATION: http://ClinicalTrials.gov, identifier NCT00808743.

Chromosome 20p11 gains are associated with liver-specific metastasis in patients with colorectal cancer.

OBJECTIVE: Metastatic colorectal cancer (CRC) cells have a selective preference for certain target organs that cannot be explained by circulatory patterns alone. This study aimed to identify clinicopathological features and chromosomal aberrations of primary tumours associated with organ-specific CRC metastasis. DESIGN: Clinicopathological features were investigated in patients with CRC who had exclusively hepatic (n=182) versus exclusively extrahepatic (n=139) metastases. A total of 139 primary tumours of patients with hepatic (n=85) and extrahepatic metastases (n=54) were screened for chromosomal aberrations by microarray-based comparative genomic hybridisation, and the findings were validated in an independent set of 80 primary tumours. A publicly available database was used to correlate chromosomal aberrations with gene expression. Protein expression was evaluated by immunohistochemistry on tissue microarrays. RESULTS: Patients with hepatic metastases were significantly more often male (71% vs 53% p=0.002), more often had abnormal lactate dehydrogenase activity (37% vs 14% p<0.0001), exhibited primary tumour localisation in the colon (52% vs 40% p=0.03) and had synchronous onset of metastases (70% vs 19% p<0.0001). Primary tumours of patients with hepatic metastases were more commonly T3 tumours (79% vs 63% p=0.006) and less commonly of mucinous histology (5% vs 16% p=0.02). Gain of 20p11 was more often observed in patients with hepatic metastases (p<0.05), which was confirmed in an independent dataset (p<0.05; false discovery rate <0.05). Twelve genes mapping at 20p11 were significantly overexpressed as a consequence of 20p11 copy number gain. C20orf3 showed the strongest correlation between RNA expression and DNA copy number. This was reflected in significantly higher protein expression in patients with hepatic metastases (59%; n=325) than in those with extrahepatic metastases (41%; n=256) (p=0.01). CONCLUSION: C20orf3 mapping at 20p11 is associated with hepatic-specific metastasis in patients with CRC. This gene is a candidate biomarker for liver metastases and may be of clinical value in early-stage CRC.

Beyond KRAS mutation status: influence of KRAS copy number status and microRNAs on clinical outcome to cetuximab in metastatic colorectal cancer patients.

BACKGROUND: KRAS mutation is a negative predictive factor for treatment with anti-epidermal growth factor receptor (EGFR) antibodies in metastatic colorectal cancer (mCRC). Novel predictive markers are required to further improve the selection of patients for this treatment. We assessed the influence of modification of KRAS by gene copy number aberration (CNA) and microRNAs (miRNAs) in correlation to clinical outcome in mCRC patients treated with cetuximab in combination with chemotherapy and bevacizumab. METHODS: Formalin-fixed paraffin-embedded primary tumour tissue was used from 34 mCRC patients in a phase III trial, who were selected based upon their good (n = 17) or poor (n = 17) progression-free survival (PFS) upon treatment with cetuximab in combination with capecitabine, oxaliplatin, and bevacizumab. Gene copy number at the KRAS locus was assessed using high resolution genome-wide array CGH and the expression levels of 17 miRNAs targeting KRAS were determined by real-time PCR. RESULTS: Copy number loss of the KRAS locus was observed in the tumour of 5 patients who were all good responders including patients with a KRAS mutation. Copy number gains in two wild-type KRAS tumours were associated with a poor PFS. In KRAS mutated tumours increased miR-200b and decreased miR-143 expression were associated with a good PFS. In wild-type KRAS patients, miRNA expression did not correlate with PFS in a multivariate model. CONCLUSIONS: Our results indicate that the assessment of KRAS CNA and miRNAs targeting KRAS might further optimize the selection of mCRC eligible for anti-EGFR therapy.

Markers for EGFR pathway activation as predictor of outcome in metastatic colorectal cancer patients treated with or without cetuximab.

BACKGROUND: Anti-EGFR monoclonal antibodies in metastatic colorectal cancer (mCRC) treatment are only effective in patients with KRAS wild type tumours. Here we assess the predictive value of other potential relevant markers involved in the epidermal growth factor receptor (EGFR) signalling pathways for response to cetuximab-based treatment. MATERIALS AND METHODS: Formalin-fixed paraffin-embedded colorectal cancer tissue of the primary tumour was obtained from 559 mCRC patients treated with chemotherapy and bevacizumab with or without cetuximab (phase III CAIRO2 study). DNA was isolated for mutation analysis of BRAF (V600E), KRAS (codon 12 and 13) and PIK3CA (exon 9 and 20). Tissue microarray's (TMA's) were constructed for the assessment of EGFR and HER2 gene copy number (GCN), and EGFR and PTEN protein expression. The results of these markers, individually or in combination, were correlated with progression-free survival (PFS) and overall survival (OS) in the subgroup of patients with a KRAS wild type tumour treated in the cetuximab-arm. KRAS wild type patients treated without cetuximab were used as a control group. RESULTS: A total of 208 tumours (39.4%) contained a KRAS mutation, 8.7% a BRAF mutation and 9.9% a PIK3CA mutation. Loss of PTEN expression and the presence EGFR protein expression were observed in 42.0% and 61.7% of the samples, respectively. An increased EGFR GCN was observed in 15.3% of the samples, and 11.5% of the evaluable samples contained an increased HER2 GCN. In KRAS wild type patients treated with cetuximab a BRAF mutation was significantly and independently associated with PFS and OS. In patients treated without cetuximab the PFS and OS were also associated with the BRAF genotype. No prognostic or predictive value was observed for any of the other markers when tested individually or in combination. CONCLUSIONS: BRAF genotype is correlated with PFS and OS in KRAS wild type mCRC patients, which is independent of cetuximab treatment. PIK3CA mutation, loss of PTEN expression, EGFR GCN and HER2 GCN have no predictive value for response to treatment with cetuximab, neither individually nor in combination with other markers.