Prediction of response to immune checkpoint blockade in patients with metastatic colorectal cancer with microsatellite instability.

BACKGROUND: Mismatch repair-deficient (dMMR) tumors displaying microsatellite instability (MSI) represent a paradigm for the success of immune checkpoint inhibitor (ICI)-based immunotherapy, particularly in patients with metastatic colorectal cancer (mCRC). However, a proportion of patients with dMMR/MSI mCRC exhibit resistance to ICI. Identification of tools predicting MSI mCRC patient response to ICI is required for the design of future strategies further improving this therapy. PATIENTS AND METHODS: We combined high-throughput DNA and RNA sequencing of tumors from 116 patients with MSI mCRC treated with anti-programmed cell death protein 1 ± anti-cytotoxic T-lymphocyte-associated protein 4 of the NIPICOL phase II trial (C1, NCT03350126, discovery set) and the ImmunoMSI prospective cohort (C2, validation set). The DNA/RNA predictors whose status was significantly associated with ICI status of response in C1 were subsequently validated in C2. Primary endpoint was progression-free survival by immune RECIST (iRECIST) (iPFS). RESULTS: Analyses showed no impact of previously suggested DNA/RNA indicators of resistance to ICI, e.g. MSIsensor score, tumor mutational burden, or specific cellular and molecular tumoral contingents. By contrast, iPFS under ICI was shown in C1 and C2 to depend both on a multiplex MSI signature involving the mutations of 19 microsatellites hazard ratio cohort C2 (HRC2) = 3.63; 95% confidence interval (CI) 1.65-7.99; P = 1.4 × 10-3] and the expression of a set of 182 RNA markers with a non-epithelial transforming growth factor beta (TGFB)-related desmoplastic orientation (HRC2 = 1.75; 95% CI 1.03-2.98; P = 0.035). Both DNA and RNA signatures were independently predictive of iPFS. CONCLUSIONS: iPFS in patients with MSI mCRC can be predicted by simply analyzing the mutational status of DNA microsatellite-containing genes in epithelial tumor cells together with non-epithelial TGFB-related desmoplastic RNA markers.

Reassessing the clinical spectrum associated with hereditary leiomyomatosis and renal cell carcinoma syndrome in French FH mutation carriers.

We addressed uncertainties regarding hereditary leiomyomatosis and renal cell carcinoma (HLRCC) by exploring all French cases, representing the largest series to date. Fumarate hydratase (FH) germline testing was performed with Sanger sequencing and qPCR/MLPA. Enzyme activity was measured when necessary. We carried out whenever possible a pathology review of RCC and S-(2-succino)-cysteine (2SC)/fumarate hydratase immunohistochemistry. We estimated survival using non-parametric Kaplan-Meier. There were 182 cases from 114 families. Thirty-seven RCC were diagnosed in 34 carriers (19%) at a median age of 40. Among the 23 RCC with pathology review, 13 were papillary type 2. There were 4 papillary RCC of unspecified type, 3 unclassified, 2 tubulocystic, and 1 collecting duct (CD) RCC, all 2SC+ and most (8/10) FH-. Of the remaining 14, papillary type 2, papillary unspecified, CD, and clear cell histologies were reported. The vast majority of RCC (82%) were metastatic at diagnosis or rapidly became metastatic. Median survival for metastatic disease was 18 months (95%CI: 11-29). 133 cases (73%) had a history of cutaneous leiomyomas, 3 developed skin leiomyosarcoma. Uterine leiomyomas were frequent in women (77%), but no sarcomas were observed. Only 2 cases had pheochromocytomas/paraganglioma. CONCLUSION: Our findings have direct implications regarding the identification and management of HLRCC patients.

[Lynch syndrome: when pathologist and clinician have the opportunity to reduce the risk of developing cancer]. / Le syndrome de lynch: pathologiste et praticien peuvent ensemble éduire le risque de cancer.

Lynch syndrome is an autosomal dominant disease associated with an important risk of cancer, mainly endometrial and colorectal-cancer. This risk can be efficiently lessen by an appropriate screening as far as the mutations carriers are identified. As current clinicopathological recommendations lack sensitivity, a systematic pre-screening of every patient with a colorectal or endometrial cancer can be proposed. Oncogenetic units of the HUG in Geneva and ICHV in Valais have set up a population-based study to evaluate the efficacy of such a strategy. Whatever the approach, the pathologist is directly implicated as Lynch syndrome harbors specific histological aspects that can help to its identification, but also as pre-screening tests are directly realized on tumor-tissue.

HapMap-based study of the 17q21 ERBB2 amplicon in susceptibility to breast cancer.

ERBB2 is frequently amplified in breast tumours as part of a wide region of amplification on chromosome 17q21. This amplicon contains many candidate genes for breast cancer susceptibility. We used a genetic association study design to determine if common genetic variation (frequency>or=5%) in a 400-kb region surrounding ERBB2 and containing the PPARBP, CRK7, NEUROD2, PPP1R1B, STARD3, TCAP, PNMT, CAB2, ERBB2, C17ORF37, GRB7 and ZNFN1A3 genes, was associated with breast cancer risk. Sixteen tagging single-nucleotide polymorphisms (tSNPs) selected within blocks of linkage disequilibrium from the HapMap database, one HapMap singleton SNP, and six additional SNPs randomly selected from dbSNP were genotyped using Taqman in a large study set of British women (2275 cases, 2280 controls). We observed no association between any of the genotypes or associated haplotypes and disease risk. In order to simulate unidentified SNPs, we performed the leave-one-out cross-validation procedure on the HapMap data; over 90% of the common genetic variation was well represented by tagging polymorphisms. We are therefore likely to have tagged any common variants present in our population. In summary, we found no association between common genetic variation in the 17q21 ERBB2 amplicon and breast cancer risk in British women.