An unusual phenotype occurs in 15% of mismatch repair-deficient tumors and is associated with non-colorectal cancers and genetic syndromes.

Immunohistochemistry (IHC) and/or MSI-PCR (microsatellite instability-polymerase chain reaction) tests are performed routinely to detect mismatch repair deficiency (MMR-D). Classical MMR-D tumors present a loss of MLH1/PMS2 or MSH2/MSH6 with MSI-High. Other profiles of MMR-D tumors have been described but have been rarely studied. In this study, we established a classification of unusual MMR-D tumors and determined their frequency and clinical impact. All MMR-D tumors identified between 2007 and 2017 were selected. Any profile besides the classical MMR-D phenotype was defined as unusual. For patients with unusual MMR-D tumors, IHC, and PCR data were reviewed, the tumor mutation burden (TMB) was evaluated and clinical and genetic features were collected. Of the 4948 cases of MMR testing, 3800 had both the available IHC and MSI-PCR results and 585 of these had MMR-D. After reviewing the IHC and PCR, 21% of the cases initially identified as unusual MMR-D were reclassified, which resulted in a final identification of 89 unusual MMR-D tumors (15%). Unusual MMR-D tumors were more often associated with non-CRC than classical MMR-D tumors. Unusual MMR-D tumors were classified into four sub-groups: i) isolated loss of PMS2 or MSH6, ii) classical loss of MLH1/PMS2 or MSH2/MSH6 without MSI, iii) four MMR proteins retained with MSI and, iv) complex loss of MMR proteins, with clinical characteristics for each sub-group. TMB-high or -intermediate was shown in 96% of the cancers studied (24/25), which confirmed MMR deficiency. Genetic syndromes were identified in 44.9% (40/89) and 21.4% (106/496) of patients with unusual and classical MMR-D tumors, respectively (P < 0.001). Five patients treated with an immune checkpoint inhibitor (ICI) had a prolonged clinical benefit. Our classification of unusual MMR-D phenotype helps to identify MMR deficiency. Unusual MMR-D phenotype occurs in 15% of MMR-D tumors. A high frequency of genetic syndromes was noted in these patients who could benefit from ICI.

Survival Outcomes of Patients with Pathologically Proven Positive Lymph Nodes at Time of Radical Cystectomy with or without Neoadjuvant Chemotherapy.

BACKGROUND: To compare overall survival (OS) outcomes in pN1-3 disease at the time of radical cystectomy (RC) for muscle invasive bladder according to the neoadjuvant chemotherapy (NAC) status. MATERIALS AND METHODS: This multicenter study included 450 consecutive patients undergoing RC for muscle-invasive urothelial bladder cancer with pN1-3 pM0 disease from 2010 to 2019. NAC consisted in platinum-based chemotherapy. The primary endpoint was the comparison between NAC and non-NAC in terms of death from any cause. OS was assessed using the Kaplan-Meier method and multivariate Cox proportional hazards regression was used to estimate adjusted hazard ratios. RESULTS: Median age was 69 years. Patients receiving NAC were younger (p = 0.051), and more likely had downstaging to non-muscle invasive disease (10.7% versus 4.3%, p = 0.042). Median OS was 26.6 months. NAC patients had poorer OS compared with those who did receive NAC (Hazard ratio (HR) 1.6; p = 0.019). The persistence of muscle-invasive bladder in RC specimens was also significantly associated with OS (HR 2.40). In the NAC cohort, the two factors independently correlated with OS were the number of positive lymph nodes (p = 0.013) and adjuvant chemotherapy (AC) (HR 0.31; p = 0.015). CONCLUSIONS: Persistent nodal disease in RC specimens after NAC was associated with poor prognosis and lower OS rates compared with pN1-3 disease after upfront RC. In this sub-group of NAC patients, AC was independently associated with better OS.

Management of gastric neuro-endocrine tumours in a large French national cohort (GTE).

INTRODUCTION: Gastric neuro-endocrine tumours are rare. European guidelines for the management of neuro-endocrine tumours have been published in 2012. The aim of our survey was to study the management of gastric neuro-endocrine tumours registered in the national cohort. A prospective national cohort registers the Neuro-endocrine tumours in France since January 2003 (GTE network). We reviewed all the individual medical reports of gastric neuro-endocrine tumours in order to collect data on treatment. RESULTS: One hundred and ninety seven gastric neuro-endocrine tumours diagnosed between 1964 and 2013 in 20 centres were registered. For 181 cases data were considered complete for our survey. Eighty four tumours were type 1 (46.4%); five types 2 (2.8%); 52 types 3 (28.7%) and 40 types 4 (22.1%). Types 1 and 2 were first endoscopically managed in 93 and 60% of cases, respectively, whereas surgery was first done in 45 and 42%, respectively, of types 3 and 4. Systemic treatment, chemotherapy and/or somatostatin analogue, was first administered exclusively for types 3 and 4. Near 3% of types 1 and 40% of types 2 received at a time somatostatin analogue treatment. Five-year survival rates were 98.3, 100, 63.2 and 31.8% for types 1, 2, 3 and 4, respectively. CONCLUSION: The great majority of gastric neuro-endocrine tumours registered in this national cohort are treated in accordance with the current guidelines. The survival rates we reported must be interpreted with caution, because this cohort registered preferentially selected patients eligible for treatment. The registration of all the gastric neuro-endocrine tumours, in particular type 1 considered as benign and type 4 not eligible for specific anti-cancer treatment must be encouraged.

Irreversible hepatotoxicity after administration of trabectedin to a pleiomorphic sarcoma patient with a rare ABCC2 polymorphism: a case report.

We describe here the case of a 60-year old male patient treated for an extensive local progression of a pleiomorphic sarcoma on the right tibial crest with second-line trabectedin. Two cycles were administrated before a major liver toxicity was retrieved, with both cytolytic and cholestatic hepatitis quickly associated with irreversible jaundice. The radiological, histological, chemistry and pharmacogenetic investigations led us to diagnose chronic hepatobiliary toxicity with portal fibrosis, cholangiolitis damages and chronic hepatopathy. The patient had a deficient variant genotype of ABCC2 (c.-24TT, c.4488CT and c.4544GA), which has been suggested to play a role in excretion of toxic metabolites of trabectedin. This case report is, to our knowledge, the first description of trabectedin's irreversible liver toxicity in a human patient. Supported by a thorough review of the literature, this hepatitis is thought to have resulted from a multihit process involving genetic variants of ABC proteins and comedication.