Prevalence and detection of actionable BRAF V600 and NRAS Q61 mutations in malignant peripheral nerve sheath tumor by droplet digital PCR

Malignant peripheral nerve sheath tumors ( MPNSTs) are aggressive tumors with poor prognosis that do not typically respond well to standard chemotherapy. Recently, point mutations involving BRAF V600E have been demonstrated in a subset of MPNST, offering the possibility of targeted treatment. However, the reported prevalence of these alterations is variable. Mutations involving NRAS, which is also involved in the MAPK/ERK pathway and amenable to targeted inhibitors, have not been well characterized in MPNST. In this study, we validated droplet digital polymerase chain reaction for the detection of BRAF V600E and NRAS Q61 mutations and evaluate the prevalence of BRAF V600E and NRAS Q61 mutations in 79 cases of MPNST, including 45 sporadic, 27 NF-1 associated, and 7 radiation-associated tumors. We detected actionable BRAF or NRAS mutations in 3 of 44 sporadic MPNSTs (6.8%), including 2 BRAF V600 and 1 NRAS Q61 mutations, as well as 1 NRAS Q61 mutation in a tumor that was ultimately considered to represent melanoma. These 3 cases with positive mutations were exclusively in sporadic, high-grade MPNST (FNCLCC grade 3 of 3), with a prevalence of 11.5% in this group (3.8% NRAS Q61 mutations and 7.7% BRAF V600 mutations). None of the tumors associated with NF-1 or prior radiation had detectable mutations in the genes tested. Overall, the prevalence of these alterations offers the possibility of targeted therapy in this aggressive type of sarcoma and suggests the potential benefit of routine clinical testing.

Anti-PD-1 in Combination With Trametinib Suppresses Tumor Growth and Improves Survival of Intrahepatic Cholangiocarcinoma in Mice

BACKGROUND & AIMS

Intrahepatic cholangiocarcinoma (iCCA) accounts for a fraction of primary liver cancers but has a 5-year survival rate of only 10%. Immune checkpoint inhibitors are effective in treating many solid cancers, but immune checkpoint inhibitor monotherapy has no clear benefit in iCCA. Mitogen-activated kinase (MEK) inhibitors, such as trametinib, have shown promising results in preclinical studies for iCCA by inhibiting cell proliferation and modifying the tumor microenvironment. This study aimed to show the potential benefit of combining trametinib with anti-programmed cell death protein 1 (PD-1) therapy in different iCCA mouse models.

METHODS

Here, we assessed the in vitro cytotoxicity of trametinib in mouse (SB1 and LD-1) and human (EGI-1) cholangiocarcinoma cell lines. We examined the efficacy of single-agent trametinib, anti-PD-1, and a combination of both in subcutaneous, orthotopic, and plasmid-induced iCCA mouse models. Flow cytometry analysis was used to elucidate changes in the tumor immune microenvironment upon treatment. Whole-exome sequencing (WES) was performed on the SB1 tumor cell line to correlate this preclinical model with iCCAs in patients.

RESULTS

Trametinib reduced tumor cell growth of SB1, LD-1, and EGI-1 tumor cells in vitro. Trametinib treatment led to up-regulation of major histocompatibility complex (MHC-I) and programmed cell death ligand 1 (PD-L-1) (programmed cell death ligand 1) on tumor cells in vitro. The combination of trametinib and anti-PD-1 reduced tumor burden in several iCCA tumor models and improved survival in SB1 tumor-bearing mice compared with either agent alone. Immunoprofiling of tumor-bearing mice showed an increase of hepatic effector memory CD8⁺ and CD4⁺ T cells, as well as an increased degranulation of CD8⁺ T cells, indicating enhanced cytotoxicity. WES and somatic mutational analysis showed no mutations of KRAS, BRAF, and ERK in SB1 tumor cells, and showed a similar genetic signature of SB1 found in a cohort of patients with iCCA.

CONCLUSIONS

Altogether, our study shows that trametinib improves the immunogenicity of tumor cells by up-regulating MHC-I surface expression. The combination with anti-PD-1 results in optimal treatment efficacy for iCCA. WES of SB1 cells suggests that KRAS wild-type iCCAs also respond to this combination therapy.

Low expression of pro-apoptotic proteins Bax, Bak and Smac indicates prolonged progression-free survival in chemotherapy-treated metastatic melanoma

Despite the introduction of novel targeted therapies, chemotherapy still remains the primary treatment for metastatic melanoma in poorly funded healthcare environments or in case of disease relapse, with no reliable molecular markers for progression-free survival (PFS) available. As chemotherapy primarily eliminates cancer cells by apoptosis, we here evaluated if the expression of key apoptosis regulators (Bax, Bak, Bcl-2, Bcl-xL, Smac, Procaspase-9, Apaf-1, Procaspase-3 and XIAP) allows prognosticating PFS in stage III/IV melanoma patients. Following antibody validation, marker expression was determined by automated and manual scoring of immunohistochemically stained tissue microarrays (TMAs) constructed from treatment-naive metastatic melanoma biopsies. Interestingly and counter-intuitively, low expression of the pro-apoptotic proteins Bax, Bak and Smac indicated better prognosis (log-rank p < 0.0001, p = 0.0301 and p = 0.0227 for automated and p = 0.0422, p = 0.0410 and p = 0.0073 for manual scoring). These findings were independently validated in the cancer genome atlas (TCGA) metastatic melanoma cohort (TCGA-SKCM) at transcript level (log-rank p = 0.0004, p = 0.0104 and p = 0.0377). Taking expression heterogeneity between the markers in individual tumour samples into account allowed defining combinatorial Bax, Bak, Smac signatures that were associated with significantly increased PFS (p = 0.0002 and p = 0.0028 at protein and transcript level, respectively). Furthermore, combined low expression of Bax, Bak and Smac allowed predicting prolonged PFS (> 12 months) on a case-by-case basis (area under the receiver operating characteristic curve (ROC AUC) = 0.79). Taken together, our results therefore suggest that Bax, Bak and Smac jointly define a signature with potential clinical utility in chemotherapy-treated metastatic melanoma.

National Burden of Hospitalization Due to Cutaneous Melanoma in Adolescents and Young Adults

OBJECTIVES

Although adolescents and young adults (AYA) suffer disproportionately from cutaneous melanoma (CM), little is known regarding the burden of CM leading to hospitalization in AYA. The objective of this study was to elucidate sociodemographic/hospitalization characteristics of AYA CM inpatients, determine which factors lead to the greater length of stay (LOS) and cost of care for AYA CM inpatients, and evaluate trends in the prevalence, LOS, and cost of care for AYA CM hospitalizations.

MATERIALS AND METHODS

A retrospective cohort study of nationally representative data from the 2009 to 2015 National Inpatient Sample. Multivariable survey-weighted logistic regression models were used to determine sociodemographic factors associated with AYA CM hospitalization. Multivariable survey-weighted linear regression models were used to determine characteristics associated with the greater cost of care and LOS in AYA CM inpatients.

RESULTS

A total of 8986 AYA CM inpatients were included in this study. The prevalence of AYA CM hospitalizations is decreasing over time while the cost of care is increasing. On average, AYA CM hospitalizations were 3.3 days long and cost $38,018.40. Controlling for all covariates, male sex, older age, non-Hispanic white race, higher income, private insurance, and elective admissions were associated with AYA hospitalization due to CM (P<0.0001). Male sex was associated with longer LOS (P=0.007) and cost of care (P=0.01) among AYA hospitalized for CM.

CONCLUSIONS

Despite a decreasing prevalence of CM hospitalizations in AYA inpatients, the economic burden of these hospitalizations is increasing. Substantial sex-based differences exist in the inpatient burden of AYA CM. Further research is required to elucidate the causes of these differences and prevent AYA hospitalization due to CM.

Patient preferences for treatment of metastatic melanoma

AIM

To investigate patient preferences for clinical attributes of first-line metastatic melanoma treatments.

MATERIALS & METHODS

A discrete-choice experiment and best-worst scaling exercise were used to assess relative preferences for treatment attributes.

RESULTS

The 200 survey respondents had distinct preferences. Avoiding a 30% risk of colitis or hormone gland problems and avoiding severe fever were more important to respondents than avoiding a 20% risk of extreme sun sensitivity (p < 0.05). Patients preferred taking pills to receiving intravenous infusions in a clinic. When attributes were combined, approximately 85% of respondents preferred a risk profile similar to targeted therapy over a profile similar to immunotherapy, holding efficacy constant.

CONCLUSION

Taking patient preferences into account can help patients get the full benefit from metastatic melanoma therapies.

Patterns of increased incidence and survival of cutaneous melanoma in Girona (Spain) 1994-2013: a population-based study

INTRODUCTION

We conducted a population-based study on the Girona Cancer Registry (Spain) for the period 1994-2013 to determine patterns of change in the incidence of melanoma, which is increasing in many countries, and patient survival in our geographical area.

MATERIALS AND METHODS

Using the standard registration rules for cancer registries, we calculated crude and standardized incidence rates as well as their trends. We also analysed the observed survival, 1-year conditioned survival and relative survival at 3, 5 and 10 years.

RESULTS

Our crude incidence rate was 9.13 cases/100,000 inhabitants for invasive and 2.59 for "in situ" melanomas. A statistically significant increase in incidence was found for melanomas of less than 1 mm in Breslow index and in males. 10-year observed and relative survival rates were 64.1 and 83.1%, respectively.

CONCLUSIONS

We found an increasing trend in the incidence of low-risk melanoma and a survival rate similar to that reported elsewhere in Europe.

A new ALK isoform transported by extracellular vesicles confers drug resistance to melanoma cells

Background

Drug resistance remains an unsolved clinical issue in oncology. Despite promising initial responses obtained with BRAF and MEK kinase inhibitors, resistance to treatment develops within months in virtually all melanoma patients.

Methods

Microarray analyses were performed in BRAF inhibitor-sensitive and resistant cell lines to identify changes in the transcriptome that might play a role in resistance. siRNA approaches and kinase inhibitors were used to assess the involvement of the identified Anaplastic Lymphoma Kinase (ALK) in drug resistance. The capability of extracellular vesicles (EVs) to transfer drug resistant properties was investigated in co-culture assays.

Results

Here, we report a new mechanism of acquired drug resistance involving the activation of a novel truncated form of ALK. Knock down or inhibition of ALK re-sensitised resistant cells to BRAF inhibition and induced apoptosis. Interestingly, truncated ALK was also secreted into EVs and we show that EVs were the vehicle for transferring drug resistance.

Conclusions

To our knowledge, this is the first report demonstrating the functional involvement of EVs in melanoma drug resistance by transporting a truncated but functional form of ALK, able to activate the MAPK signalling pathway in target cells. Combined inhibition of ALK and BRAF dramatically reduced tumour growth in vivo. These findings make ALK a promising clinical target in melanoma patients.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0886-x) contains supplementary material, which is available to authorized users.

Phase II study of pazopanib in combination with paclitaxel in patients with metastatic melanoma

PURPOSE

This phase II study evaluated the safety and clinical activity of pazopanib, a potent and mutlitargeted tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor receptors (VEGFRs)-1, -2 and -3, platelet-derived growth factor receptor (PDGFR)-α and β, and cKit, in combination with metronomic paclitaxel in patients with metastatic melanoma.

EXPERIMENTAL DESIGN

Sixty chemotherapy-naive patients received pazopanib at a starting dose of 800 mg daily in combination with metronomic dosing of paclitaxel 80 mg/m² weekly thrice every 4 weeks. The primary endpoint was 6-month progression-free survival (PFS) rate, while secondary endpoints included 1-year overall survival rate, RECIST response rates, progression-free survival rates and median overall survival. Prior BRAF-targeted therapy or checkpoint inhibitors were permitted.

RESULTS

The 6-month PFS rate was 68%, with a 1-year OS rate of 48%. Objective response rate was 37% comprising one complete and 20 partial responses. Stable disease at 8 weeks was noted in 32 patients (55%) with an overall clinical benefit rate of 93%. Six-month median progression-free survival was 8 months and median OS was 12.7 months. The most frequently (> 15%) reported non-hematologic, treatment-related adverse events were fatigue, diarrhea, hypertension, transaminitis and peripheral neuropathy. Treatment-related non-fatal bowel perforation, a known class effect, occurred in one patient. No significant association was noted between plasma levels of pazopanib and response.

CONCLUSIONS

The combination of pazopanib and metronomic paclitaxel was well-tolerated, demonstrating significant activity in metastatic melanoma. Further evaluation of this combination is warranted.

Synthesis of a Sulfonimidamide-Based Analog of Tasisulam and Its Biological Evaluation in the Melanoma Cell Lines SKMel23 and A375

Tasisulam is a promising antitumor agent with complex pharmacology, which is used as an antiproliferative agent in patients with metastatic melanoma and other solid tumors. Phase 2 melanoma studies showed promising results but had to be stopped because of insufficient tasisulam clearance leading to toxic side effects. To reduce the negative effects of tasisulam, we synthesized a novel sulfonimidamide-based analog to evaluate its antiproliferative effects in comparison to the original compound by performing a cell proliferation assay in melanoma cell lines SKMel23 and A375. The results revealed that the analog had inhibitory effects on the proliferation comparable to tasisulam in both investigated cell lines. These results could contribute to a reduced toxicity of tasisulam and lead to further clinical trials in metastatic melanoma.