Mutagenicity of N3-methyladenine: a multi-translesion polymerase affair.

We recently demonstrated that Polzeta and Rev1 contribute to alleviate the lethal effects of Me-lex, which selectively generates 3-methyladenine, by error prone lesion bypass. In order to determine the role of Poleta in the biological fate of Me-lex induced lesions, the RAD30 (Poleta) gene was deleted in the yIG397 parental strain and in its rev3 (Polzeta) derivative, and the strains transformed with plasmid DNA damaged in vitro by Me-lex. While deletion of RAD30 increased the toxicity of Me-lex, the impact on mutagenicity varied depending on the concentration of Me-lex induced DNA damage and the overall TLS capacity of the cells. For the first time the Me-lex induced mutation spectrum in rad30 strain was determined and compared with the spectrum previously determined in WT strain. Overall, the two mutation spectra were not significantly different. The effect on mutation frequency and the features of the Me-lex induced mutation spectra were suggestive of error prone (significant decrease of mutation frequency and significant decrease of AT>TA at a mutation hotspot in rad30 vs RAD30) but also error free (significant increase of AT>GC in rad30 vs RAD30) Poleta dependent bypass of lesions. In summary, our previous results with Polzeta and Rev1 mutants, the present results with Poleta, and the known physical and functional interactions among TLS proteins, lead us to propose that the bypass of Me-lex induced lesions is a multi-DNA polymerases process that is mostly effective when all three yeast TLS polymerases are present.

Reliability of programmed death ligand 1 (PD-L1) tumor proportion score (TPS) on cytological smears in advanced non-small cell lung cancer: a prospective validation study.

INTRODUCTION: Programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) assessment is mandatory for the single agent pembrolizumab treatment of patients with advanced non-small cell lung cancer (NSCLC). PD-L1 testing has been validated and is currently certified only on formalin-fixed paraffin-embedded materials but not on cytological smears. Unfortunately, a significant proportion of patients, having only cytological material available, cannot be tested for PD-L1 and treated with pembrolizumab. In this study, we aimed to validate PD-L1 IHC on cytological smears prospectively by comparing clone SP263 staining in 150 paired histological samples and cytological smears of NSCLC patients. METHODS: We prospectively enrolled 150 consecutive advanced NSCLC patients. The clone SP263 was selected as, in a previous study of our group, it showed higher accuracy compared with clones 28-8 and 22-C3, with good cyto-histological agreement using a cut-off of 50%. For cyto-histological concordance, we calculated the kappa coefficient using two different cut-offs according to the percentage of PD-L1 positive neoplastic cells (<1%, 1-49% and ⩾50%; <50%, ⩾50%). RESULTS: The overall agreement between histological samples and cytological smears was moderate (kappa = 0.537). However, when the cyto-histological concordance was calculated using the cut-off of 50%, the agreement was good (kappa = 0.740). With the same cut-off, and assuming as gold-standard the results on formalin-fixed paraffin-embedded materials, PD-L1 evaluation on smears showed specificity and negative predictive values of 98.1% and 93.9%, respectively. CONCLUSION: Cytological smears can be used in routine clinical practice for PD-L1 assessment with a cut-off of 50%, expanding the potential pool of NSCLC patients as candidates for first-line single agent pembrolizumab therapy.

The evolving landscape of immunotherapy in small-cell lung cancer: A focus on predictive biomarkers.

Small cell lung cancer (SCLC) was defined as a "recalcitrant cancer" because of its dismal prognosis and lack of outcome improvements in the last 30 years. Immunotherapy with checkpoint inhibitors revolutionized treatment in many cancer types and results from the IMpower133 study, a double-blind placebo-controlled phase III trial, showed overall survival benefit for atezolizumab when added to standard platinum-etoposide chemotherapy in first-line SCLC setting for the first time since years. Trials with other checkpoint inhibitors, e.g. pembrolizumab, durvalumab, nivolumab and ipilimumab, are ongoing in various settings, but, to date, there are no defined factors to identify patients who are more likely to benefit from such treatments. This review summarizes results of immunotherapy trials in SCLC for first-line, maintenance and further-line therapies for single-agents and combinations with checkpoint inhibitors. Predictive factors from these trials are reviewed in order to identify their clinical value, with particular emphasis on PD-L1 expression on both tumor cells and in stroma, especially in pembrolizumab-treated patients, and tumor mutational burden, for patients treated with the ipilimumab and nivolumab combination.

Validation of the immunohistochemical expression of programmed death ligand 1 (PD-L1) on cytological smears in advanced non small cell lung cancer.

Introduction The assessment of PD-L1 expression by immunohistochemistry is mandatory for the administration as first-line therapy of the anti PD-1 check-point inhibitor Pembrolizumab in patients with advanced non-small-cell lung cancer (NSCLC). Currently, only formalin-fixed paraffin-embedded samples are acceptable for PD-L1 immunostaining with the anti-PD-L1 antibodies 22-C3 and SP263. We investigated retrospectively the accuracy of the anti PD-L1 antibodies 22-C3, 28-28, SP263 in 50 paired histological samples and cytological smears of NSCLC patients. Results The accuracy of the three antibodies for the detection of PD-L1 in histological samples was higher for the antibody SP263 (AUC/ROC = 1) compared to the clones 28-8 (AUC/ROC =,991) and 22-C3 (AUC/ROC =,942). The overall concordance between histological samples and cytological smears using the SP263 clone was moderate (kappa = 0,364). However when the cyto-histological concordance was calculated using just the <50% vs ≥50% cut-off the agreement (kappa = 0.626) was good. The accuracy of the antibody SP263 in cytological smears was good (AUC/ROC =,921). A fluorescent in situ hybridization analysis on 10 histological cases positive for PD-L1 at immunohistochemistry showed amplification of the CD274 gene only in one case. Conclusions Immunocytochemical staining for PD-L1 in diagnostic cytological smears of NSCLC is feasible and applicable at least using the >50% cancer cell cut-off. The three antibodies SP263, 22-C3 and 28-8 are all suitable for the diagnostic detection of PD-L1 on tissue sections with a superiority of the SP263 clone. The implementation of PD-L1 immunocytochemistry on cytological smears will likely expand the pool of NSCLC patients candidate to first-line immunotherapy.

Pembrolizumab in the treatment of metastatic non-small cell lung cancer: a review of current evidence.

Immune checkpoint inhibitors (ICPIs) are considered one of the most important breakthroughs in cancer treatment of the past decade; notably, different studies of programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) inhibitors have reported impressive clinical activity and durable responses in patients with advanced non-small cell lung cancer (NSCLC). These findings have led to the changing of the current therapeutic algorithm of advanced NSCLC, adding a new standard first-line treatment option for patients with PD-L1-positive tumors. Pembrolizumab, a highly selective anti-PD-1 humanized monoclonal antibody, was approved by the United States Food and Drug Administration (US FDA) in October 2016 for previously untreated metastatic NSCLC patients whose tumors have high PD-L1 expression, tumor proportion score (TPS) ⩾ 50%, as well as for metastatic NSCLC patients whose tumors express PD-L1 with TPS ⩾ 1% progressing on or after platinum-based chemotherapy. However, many issues remain outstanding, mainly regarding the identification of an optimal biomarker which can help selecting patients more likely to respond to ICPIs. In this review, we discuss the clinical results obtained so far with the anti-PD-1 pembrolizumab in advanced NSCLC, commenting on the role of PD-L1 as a predictive factor and providing an update of the future perspectives.

The safety and efficacy of enzalutamide in the treatment of advanced prostate cancer.

INTRODUCTION: Enzalutamide - a non-steroidal second-generation antiandrogen - represents an active treatment option for patients with metastatic castration-resistant prostate cancer (mCRPC) in both chemotherapy-naïve and docetaxel-pretreated settings, based on the demonstration of improved overall survival over placebo in two large phase III trials. AREAS COVERED: The therapeutic landscape of mCRPC, narrowed to docetaxel until recently, encompasses now several treatments of a different nature (including androgen receptor targeting agents, taxanes, radiometabolic therapy, and immunotherapy), improving considerably the patients prognosis. However, direct comparisons between these agents still lack, raising the question of the optimal sequence of treatment. Expert commentary: We described in detail available data on clinical efficacy and safety of enzalutamide in different clinical settings (chemotherapy-naïve and -pretreated mCRPC patients), analyzing patients characteristics, the effects of enzalutamide on major clinical outcomes and its impact on patients quality of life. Finally, we briefly overviewed ongoing clinical trials evaluating potential active combinations, cross-resistance with other compounds, sequential strategies, and possible prognostic or predictive biomarkers.

Mesothelin in serum and pleural effusion in the diagnosis of malignant pleural mesothelioma with non-positive cytology.

BACKGROUND/AIM: Mesothelin (SMRP) is regarded as a biomarker of malignant pleural mesothelioma (MPM). Herein, we analyzed the contribution of SMRP detection in pleural effusion and in serum to the diagnosis of MPM with non-positive cytology. MATERIALS AND METHODS: The present study included 52 cases of MPM, 43 of pleural benign lesions and 25 of non-MPM pleural metastases. SMRP was measured by MesoMark ELISA (Cis-Bio International Gif/Yvette; France). RESULTS: In non-positive cytology, effusion-SMRP showed higher diagnostic performance than serum-SMRP. We found 38 out of 52 (73.1%) cases of non-positive cytology MPM, out of which 27 (71.0%) were positive for effusion-SMRP (cut-off=12.70 nM) and 18 (47.4%) for serum-SMRP (cut-off=1.08 nM). When cytology, effusion- and serum-SMRP were used in combination, an overall sensitivity in detection of MPM of 78.9% was achieved. The same sensitivity was obtained by combining cytology with effusion-SMRP alone, whereas the combination of serum-SMRP with cytology led to a sensitivity of 61.5%. CONCLUSION: Detection of both effusion- and serum-SMRP can contribute to improve the diagnosis of MPM with non-positive cytology. However, the analysis of SMRP in effusion makes it unnecessary to test SMRP in the serum.