Molecular alterations in genes involved in DNA mismatch repair (MMR) promote cancer initiation and foster tumour progression. Cancers deficient in MMR frequently show favourable prognosis and indolent progression. The functional basis of the clinical outcome of patients with tumours that are deficient in MMR is not clear. Here we genetically inactivate MutL homologue 1 (MLH1) in colorectal, breast and pancreatic mouse cancer cells. The growth of MMR-deficient cells was comparable to their proficient counterparts in vitro and on transplantation in immunocompromised mice. By contrast, MMR-deficient cancer cells grew poorly when transplanted in syngeneic mice. The inactivation of MMR increased the mutational burden and led to dynamic mutational profiles, which resulted in the persistent renewal of neoantigens in vitro and in vivo, whereas MMR-proficient cells exhibited stable mutational load and neoantigen profiles over time. Immune surveillance improved when cancer cells, in which MLH1 had been inactivated, accumulated neoantigens for several generations. When restricted to a clonal population, the dynamic generation of neoantigens driven by MMR further increased immune surveillance. Inactivation of MMR, driven by acquired resistance to the clinical agent temozolomide, increased mutational load, promoted continuous renewal of neoantigens in human colorectal cancers and triggered immune surveillance in mouse models. These results suggest that targeting DNA repair processes can increase the burden of neoantigens in tumour cells; this has the potential to be exploited in therapeutic approaches.

Purpose: BRAF mutations are grouped in activating RASindependent signaling as monomers (class 1-V600E) or as dimers (class 2-codons 597/601), and RAS-dependent with impaired kinase activity (class 3-codons 594/596). Although clinical, pathologic, and molecular features of V600E BRAFmutated metastatic colorectal cancer (mCRC) are well known, limited data are available from the two other classes. Experimental Design: Data from 117 patients with BRAF (92 class 1, 12 class 2, and 13 class 3)-mutated mCRC were collected. A total of 540 BRAF wt mCRCs were included as control. IHC profiling was performed to determine the consensus molecular subtypes (CMS), cytokeratin 7/20 profiles, tumor-infiltrating lymphocyte infiltration, and BM1/BM2 categorization. Overall survival (OS) and progression-free survival were evaluated by Kaplan-Meier and log-rank test. Results: Class 3 BRAF-mutated mCRC was more frequently left sided (P ¼ 0.0028), pN0 (P ¼ 0.0159), and without peritoneal metastases (P ¼ 0.0176) compared with class 1, whereas class 2 cases were similar to class 1. Hazard ratio for OS, as compared with BRAF wt, was 2.38 [95% confidence interval (CI), 1.61-3.54] for class 1, 1.90 (95% CI, 0.85-4.26) for class 2, and 0.93 (95% CI, 0.51-1.69) for class 3 (P < 0.0001). Class 2 and 3 tumors were all assigned to CMS2-3. A higher median CD3/CD8-positive lymphocyte infiltration was observed in BRAF-mutated class 2 (P ¼ 0.033) compared with class 3 cases. Conclusions: For the first time, different clinical and pathologic features and outcome data were reported according to the three BRAF mutation classes in mCRC. Specific targeted treatment strategies should be identified in the near future for such patients.

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Background: The aim of this study was to compare outcomes of immediate prosthetic breast reconstruction (IPBR) using traditional submuscular (SM) positioning of implants versus prepectoral (PP) positioning of micropolyurethane-foam-coated implants (microthane) without further coverage. Methods: We retrospectively reviewed the medical records of breast cancer patients treated by nipple-sparing mastectomy (NSM) and IPBR in our institution during the two-year period from January 2018 to December 2019. Patients were divided into two groups based on the plane of implant placement: SM versus PP. Results: 177 patients who received IPBR after NSM were included in the study; implants were positioned in a SM plane in 95 patients and in a PP plane in 82 patients. The two cohorts were similar for mean age (44 years and 47 years in the SM and PP groups, respectively) and follow-up (20 months and 16 months, respectively). The mean operative time was 70 min shorter in the PP group. No significant differences were observed in length of hospital stay or overall major complication rates. Statistically significant advantages were observed in the PP group in terms of aesthetic results, chronic pain, shoulder dysfunction, and skin sensibility (p < 0.05), as well as a trend of better outcomes for sports activity and sexual/relationship life. Cost analysis revealed that PP-IPBR was also economically advantageous over SM-IPBR. Conclusions: Our preliminary experience seems to confirm that PP positioning of a polyurethane-coated implant is a safe, reliable and effective method to perform IPBR after NSM.

Taken together, these results support a possible anti-cancer and anti-angiogenetic activity of Zol. Our data may not only provide a basis for the clinical use of this drug as preventive agent of bone metastases but also suggest that Zol deserves attention as an anti-cancer agent in non-small-cell lung cancer.

Background: Despite the well-known negative prognostic value of the V600E BRAF mutation in patients with metastatic colorectal cancer (mCRC), its outcome is quite heterogeneous, and the basis for this prognostic heterogeneity should be better defined. Methods: Two large retrospective series of V600E BRAF-mutated mCRC from 22 institutions served as an exploratory and validation set to develop a prognostic score. The model was internally and externally validated. Results: A total of 395 V600E BRAF-mutated mCRCs were included in the exploratory set. Performance status, CA19.9, lactate dehydrogenase, neutrophil/lymphocyte ratio, grading and liver, lung and nodal involvement emerged as independent prognostic factors for overall survival (OS). Two different scoring systems were built: a 'complete' score (0e16) including all significant covariates and a 'simplified' score (0e9), based only on clinicopathological covariates, and excluding laboratory values. Adopting the complete score, proportions of patients with a low (0e4), intermediate (5e8) and high (9e16) score were 44.7%, 42.6% and 12.6%, respectively. The median OS was 29.6, 15.5 (hazard ratio [HR] for intermediate vs low risk: 2.16, 95% confidence interval [CI]: 1.44e3.22, p < .001) and 6.6 months (HR for high vs low risk: 4.72, 95% CI: 2.72e8.20, p < .001). Similar results were observed also after adjusting for the type of first-line treatment and adopting the simplified score. The simplified prognostic score derived from the exploratory set was then applied to the validation set for external confirmation. Conclusions: These scoring systems are based on easy-to-collect data and defined specific subgroups with relevant differences in their life expectancy. These tools could be useful in clinical practice, would allow better stratification of patients in clinical trials and may be adopted for proper adjustments in exploratory translational analyses.

Hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer is the most common breast cancer subtype, and endocrine therapy (ET) remains its therapeutic backbone. Although anti-estrogen therapies are usually effective initially, approximately 50% of HR+ patients develop resistance to ET within their lifetime, ultimately leading to disease recurrence and limited clinical benefit. The recent addition of cyclin-dependent kinase 4 (CDK4) and CDK6 inhibitors (palbociclib, ribociclib, abemaciclib) to ET have remarkably improved the outcome of patients with HR+ advanced breast cancer (ABC) compared with anti-estrogens alone, by targeting the cell-cycle machinery and overcoming some aspects of endocrine resistance. However, which patients are the better candidates for these drugs, which are the main characteristics for a better selection of patients or if there are predictive biomarkers of response, is still unknown. In this review we reported the mechanism of action of CDK4/6 inhibitors as well as their potential mechanism of resistance, their implications in clinical practice and the forthcoming strategies to enhance their efficacy in improving survival and quality of life of patients affected with HR+, HER2−, ABC.