Prognostic and clinicopathological utility of programmed death-ligand 1 in malignant pleural mesothelioma: A meta-analysis

ObjectiveProgrammed death ligand 1 (PD-L1) has been reported to be connected to prognosis in individuals with malignant pleural mesothelioma (MPM), although there is no consensus based on data from previous studies. Accordingly, this quantitative meta-analysis investigated prognostic and clinicopathological utility of PD-L1 in patients with MPM.MethodsA comprehensive search of the PubMed, Web of Science, Embase, and Cochrane Library databases for articles published up to October 4, 2019 was performed. Studies using immunohistochemical techniques to detect/quantify the expression of PD-L1 in MPM tissue were enrolled in the analysis. The combined hazard ratio (HR) and corresponding 95% confidence interval (CI) was applied to assess the association between PD-L1 expression and overall survival (OS).ResultsA total of 11 studies comprising 1606 patients was included in the present meta-analysis. For OS, pooled data revealed an HR of 1.50 (95% CI 1.32–1.70; p < 0.001), suggesting that patients with PD-L1 overexpression experience inferior OS. Subgroup analysis revealed that elevated PD-L1 remained a significant prognostic indicator for worse OS, irrespective of sample size, cut-off value, ethnicity, and Newcastle-Ottawa Scale score. Moreover, PD-L1 overexpression was associated with non-epithelioid histology (odds ratio 4.30 [95% CI 1.89–9.74]; p < 0.001).ConclusionsResults of this meta-analysis show that elevated expression of PD-L1 could be a factor predicting poorer survival in patients with MPM.     

CTLA4 antagonists in phase I and phase II clinical trials,current status and future perspectives for cancer therapy

Introduction: In cancer, the immune response to tumor antigens is often suppressed by inhibitors and ligands. Checkpoint blockade, considered one of the most promising frontiers for anti-cancer therapy, aims to stimulate the immune anti-cancer response. Agents such as cytotoxic T lymphocyte–associated antigen 4 (CTLA-4) inhibitors offer prolonged survival with manageable side effects.

Areas covered: We summarize the recent clinical successes of CTLA-4 inhibitors and place a strong emphasis on those in early phase clinical trials, often in combination with other immune check-point inhibitors, i.e., programmed cell death protein 1 (PD-1) and BRAF/mitogen-activated protein kinase inhibitors.

Expert opinion: Recent phase I and phase II clinical trials confirm the efficacy of anti-CTLA-4 therapy for treatment of cancers such as renal cell carcinoma. These studies also indicated increased efficacy with combined immune checkpoint blockade with PD-1 or Ras/Raf/mitogen-activated protein kinase/ERK kinase (MEK)/extracellular-signal-regulated kinase (ERK) inhibitors. Researchers must search for new immune targets that may enable more effective and safe immune checkpoint blockade and cancer therapy. This goal may be achieved by next-generation combination therapies to overcome immune checkpoint therapy resistance.     

Relationship between MLH1, PMS2, MSH2 and MSH6 gene-specific alterations and tumor mutational burden in 1057 microsatellite instability-high solid tumors

Microsatellite instability-high (MSI-H) and tumor mutational burden (TMB) are predictive biomarkers for immune-checkpoint inhibitors (ICIs). Still, the relationship between the underlying cause(s) of MSI and TMB in tumors remains poorly defined. We investigated associations of TMB to mismatch repair (MMR) protein expression patterns by immunohistochemistry (IHC) and MMR mutations in a diverse sample of tumors. Hypothesized differences were identified by the protein/gene affected/mutated and the tumor histology/primary site. Overall, 1057 MSI-H tumors were identified from the 32 932 tested. MSI was examined by NGS using 7000+ target microsatellite loci. TMB was calculated using only nonsynonymous missense mutations sequenced with a 592-gene panel; a subset of MSI-H tumors also had MMR IHC performed. Analyses examined TMB by MMR protein heterodimer impacted (loss of MLH1/PMS2 vs. MSH2/MSH6 expression) and gene-specific mutations. The sample was 54.6% female; mean age was 63.5 years. Among IHC tested tumors, loss of co-expression of MLH1/PMS2 was more common (n = 544/705, 77.2%) than loss of MSH2/MSH6 (n = 81/705, 11.5%; P < .0001), and was associated with lower mean TMB (MLH1/PMS2: 25.03 mut/Mb vs MSH2/MSH6 46.83 mut/Mb; P < .0001). TMB also varied by tumor histology: colorectal cancers demonstrating MLH1/PMS2 loss had higher TMBs (33.14 mut/Mb) than endometrial cancers (20.60 mut/Mb) and other tumors (25.59 mut/Mb; P < .0001). MMR gene mutations were detected in 42.0% of tumors; among these, MSH6 mutations were most common (25.7%). MSH6 mutation patterns showed variability by tumor histology and TMB. TMB varies by underlying cause(s) of MSI and tumor histology; this heterogeneity may contribute to differences in response to ICI.     

Emerging from their burrow: Hedgehog pathway inhibitors for cancer

Introduction: Cancer treatment is moving away from conventional cytotoxic drugs and towards agents that target specific proteins and mechanisms important to cancer development or survival. The Hedgehog Pathway (HhP) is a signal transduction pathway and its constitutive activation is tumorigenic in basal cell carcinoma (BCC). The HhP enables phenotypic flexibility, and channels tumor-stroma interactions. As a result, it is over-expressed in numerous cancers as well as in the tumor microenvironment and may represent a promising therapeutic target.

Areas covered: In this article, we review the rationale for targeting HhP and its role as an oncogenic driver, in tumor epithelial-to-mesenchymal transition (EMT), and in the tumor microenvironment and describe the results of preclinical and clinical studies involving HhP inhibitors.

Expert opinion: HhP activation plays an important role in both the tumor microenvironment and tumor EMT which can lead to treatment resistance for a number of different malignancies. In addition to standard use in BCC, several HhP inhibitors are in preclinical, early, and mid-stage clinical development for other solid and hematologic malignancies.     

Incidence of T790M in Patients With NSCLC Progressed to Gefitinib,Erlotinib, and Afatinib: A Study on Circulating Cell-free DNA

BackgroundInsights into the mechanism of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) could provide important information for further patient management, including the choice of second-line treatment. The EGFR T790M mutation is the most common mechanism of resistance to first- and second-generation EGFR TKIs. Owing to its biologic relevance in the response of non–small-cell lung cancer (NSCLC) to the selective pressure of treatment, the present study investigated whether the occurrence of T790M at progression differed among patients receiving gefitinib, erlotinib, or afatinib.Patients and MethodsThe present retrospective study included patients with NSCLC with an EGFR activating mutation, who had received gefitinib, erlotinib, or afatinib as first-line treatment. Plasma samples for the analysis of cell-free DNA were taken at disease progression and analyzed using a digital droplet polymerase chain reaction EGFR mutation assay.ResultsA total of 83 patients were enrolled; 42 had received gefitinib or erlotinib and 41afatinib. The patient characteristics were comparable across the 2 groups. The median time to progression (TTP) was 14.4 months for the gefitinib and erlotinib group and 10.2 months for the afatinib group (P = .09). Of the 83 patients, 47 (56.6%) were positive for the T790M in plasma. A greater incidence of T790M was observed in patients with progression during gefitinib or erlotinib therapy compared with patients treated with afatinib (33 [79%] vs. 14 [34%], respectively; odds ratio, 7.1; 95% confidence interval, 2.7-18.5; P = .0001).ConclusionsAlthough gefitinib, erlotinib, and afatinib showed a comparable TTP in patients receiving first-line therapy, the incidence of T790M differed among them, as demonstrated by the present study, which could have implications for the choice of second-line treatment.     

Association Between Clinical Tumor Burden and Efficacy of Immune Checkpoint Inhibitor Monotherapy for Advanced Non–Small-Cell Lung Cancer

BackgroundProgrammed cell death 1 (PD-1) inhibitors have become a standard treatment, albeit not completely effective, for patients with advanced non–small-cell lung cancer (NSCLC). Previous studies of advanced melanoma have revealed that the tumor burden predicted the response to PD-1 inhibitors, although this relationship has remained unclear for NSCLC.Patients and MethodsThe present single-center retrospective study evaluated 163 patients with advanced NSCLC who had received PD-1/programmed cell death ligand 1 (PD-L1) inhibitor monotherapy from December 2015 to December 2018. The clinical tumor burden was estimated using the baseline sum of the target lesions’ longest diameters (BSLDs), measured according to the Response Evaluation Criteria for Solid Tumors, and the baseline number of metastatic lesions (BNMLs).ResultsThe optimal cutoff values for predicting progression-free survival (PFS) were 5 for the BNMLs and 76 mm for the BSLDs, using the minimum P value method. The low-BNML group included 73 patients (44.8%). The median PFS was 12.2 months in the low-BNML group and 2.8 months in the high-BNML group (hazard ratio, 0.51; P = .0005). The low-BSLD group included 92 patients (56.4%). The median PFS was 9.6 months in the low-BSLD group and 3.4 months in the high-BSLD group (hazard ratio, 0.52; P = .0006). Multivariable analysis revealed that low-BSLD, low-BNML, nonsquamous histologic type and a PD-L1 tumor proportion score of ≥ 50% were independently associated with prolonged PFS.ConclusionsPD-L1 expression and the clinical tumor burden can predict the efficacy of PD-1/PD-L1 inhibitor monotherapy for NSCLC.     

Perioperative,short-, and long-term outcomes of gastric cancer surgery: Propensity score-matched analysis of patients with or without prior solid organ transplantation

BackgroundDetails of perioperative outcomes and survival after gastric cancer surgery in prior transplant recipients have received minimal research attention.MethodsWe performed an observational cohort study using the database of 20,147 gastric cancer patients who underwent gastrectomy at a single gastric cancer center in Korea. Forty-one solid organ recipients [kidney (n = 35), liver (n = 5), or heart (n = 1)] were matched with 205 controls using propensity score matching.ResultsOperation time, blood loss, and postoperative pain were similar between groups. Short-term complication rates were similar between transplantation and control groups (22.0% vs. 20.1%, P = 0.777). Transplantation group patients with stage 1 gastric cancer experienced no recurrence, while those with stage 2/3 cancer had significantly higher recurrence risk compared to the controls (P = 0.049). For patients with stage 1 cancer, the transplantation group had a significantly higher rate of non-gastric cancer-related deaths compared to the controls (19.2% vs. 1.4%, P = 0.001). For those with stage 2/3 cancer, significantly lower proportion of the transplantation group received adjuvant chemotherapy compared to the control group (26.7% vs. 80.3%, P < 0.001). The transplantation group had a higher (albeit not statistically significant) rate of gastric cancer-related deaths compared to the controls (40.0% vs. 18.0%, P = 0.087).ConclusionTransplant recipients and non-transplant recipients exhibited similar perioperative and short-term outcomes after gastric cancer surgery. From long-term outcome analyses, we suggest active surveillance for non-gastric cancer-related deaths in patients with early gastric cancer, as well as strict oncologic care in patients with advanced cancer, as effective strategies for transplant recipients.     

The Current Role of Calcineurin Inhibitors in Posttransplant Immunosuppression?

It is important to determine when to use and when to avoid calcineurin inhibitors (CNIs). CNIs are associated with kidney dysfunction in some, but not all, transplant recipients. CNI-sparing protocols have their own drug-specific limitations. Two major clinical series suggest the benefit of routine CNI-sparing approaches, but our review suggests weaknesses in both. Ongoing studies are needed to determine which subgroups of recipients will benefit from CNIs.     

血管生成抑制剂YH-16联合氟尿嘧啶抑制结直肠癌肝转移的研究

目的探讨血管生成抑制剂YH-16和氟尿嘧啶（5-FU）联合应用对结直肠癌肝转移的抑制作用。方法用MTT方法测定血管生成抑制剂YH-16和5-FU对血管内皮细胞和结肠癌细胞的IC50；建立小鼠肝转移模型。随机分为对照组、YH-16组（又分为低、中、高剂量3组）和5-Fu组及联合治疗组（YH-16加5-FU），术后2周观察各组小鼠肝转移瘤数目、原发灶大小和毒性反应。并检测肝转移瘤血管内皮生长因子（VEGF）的表达和肿瘤微血管密度（MVD）。结果YH-16对结肠癌细胞的IC50是血管内皮细胞的3．38倍，而5-Fu对两种细胞的IC50差别不大。高剂量YH-16组、5-FU组和联合治疗组肝转移瘤数目明显低于对照组。而联合治疗组又低于高剂量YH-16组和5-FU组（均P〈0．05）。YH-16各剂量组的脾原发瘤体积与对照组比较均P〉0．05。差异无统计学意义；而5-FU组和联合治疗组则小于对照组（均P〈0．05）。YH-16的毒性明显低于5-FU（P〈0．05），且两者联合使用其毒性与单用5-FU比较，差异无统计学意义（P〉0．05）。5-FU组和联合治疗组肝转移瘤组织中VEGF的表达明显降低，中、高剂量YH-16组和5-FU组及联合治疗组肝转移瘤组织中的MVD计数明显降低（均P〈0．05）。结论血管生成抑制剂YH-16明显抑制结直肠癌肝转移，YH-16与5-FU联合应用对结直肠癌肝转移的抑制具有协同作用。