Using a Recently Approved Tumor Mutational Burden Biomarker to Stratify Patients for Immunotherapy May Introduce a Sex Bias

The role of the sex hormone-gut microbiome axis in tumor immunotherapy

Accumulating evidence suggested that both gut microbiome and sex play a critical role in the efficacy of immune checkpoint blockade therapy. Considering the reciprocal relationship between sex hormones and gut microbiome, the sex hormone-gut microbiome axis may participate in the regulation of the response to immune checkpoint inhibitors (ICIs). In this review, it was attempted to summarize the current knowledge about the influences of both sex and gut microbiome on the antitumor efficacy of ICIs and describe the interaction between sex hormones and gut microbiome. Accordingly, this review discussed the potential of enhancing the antitumor efficacy of ICIs through regulating the levels of sex hormones through manipulation of gut microbiome. Collectively, this review provided reliable evidence concerning the role of the sex hormone-gut microbiome axis in tumor immunotherapy.

Genetic and Clinical Characteristics of ARID1A Mutated Melanoma Reveal High Tumor Mutational Load without Implications on Patient Survival

Simple Summary

Melanoma is a highly malignant skin cancer with the highest mortality of all cutaneous tumors. Relevant genetic events have been identified, which shape the tumor and also the response to treatment. Recurrent ARID1A mutations have been identified, which are associated with improved outcomes to immune checkpoint inhibition in various tumors. Not much was known about the role of ARID1A mutations in melanoma to date. We investigated the largest cohort of ARID1A mutated melanoma to date and were able to show that despite a high mutational load the described beneficial treatment response is not apparent in melanoma.

Abstract

(1) Background: Melanoma has the highest mortality of all cutaneous tumors, despite recent treatment advances. Many relevant genetic events have been identified in the last decade, including recurrent ARID1A mutations, which in various tumors have been associated with improved outcomes to immunotherapy. (2) Methods: Retrospective analysis of 116 melanoma samples harboring ARID1A mutations. Assessment of clinical and genetic characteristics was performed as well as correlations with treatment outcome applying Kaplan–Meier (log-rank test), Fisher’s exact and Chi-squared tests. (3) Results: The majority of ARID1A mutations were in cutaneous and occult melanoma. ARID1A mutated samples had a higher number of mutations than ARID1A wild-type samples and harbored UV-mutations. A male predominance was observed. Many samples also harbored NF1 mutations. No apparent differences were noted between samples harboring genetically inactivating (frame-shift or nonsense) mutations and samples with other mutations. No differences in survival or response to immunotherapy of patients with ARID1A mutant melanoma were observed. (4) Conclusions: ARID1A mutations primarily occur in cutaneous melanomas with a higher mutation burden. In contrast to findings in other tumors, our data does not support ARID1A mutations being a biomarker of favorable response to immunotherapies in melanoma. Larger prospective studies would still be warranted.

Potential Reasons for Unresponsiveness to Anti-PD1 Immunotherapy in Young Patients with Advanced Melanoma

The impact of age on the clinical benefit of anti-PD1 immunotherapy in advanced melanoma patients has been evolving recently. Due to a reduced immune function in elderly patients, young patients with a robust immune system are theoretically expected to benefit more from the treatment approach. However, in contrast to this hypothesis, recent studies in patients with metastatic melanoma have demonstrated that immunotherapy, especially with anti-PD1 treatment, is less effective in patients below 65 years, on average, with significantly lower responses and reduced overall survival compared to patients above 65 years of age. Besides, data on young patients are even more sparse. Hence, in this review, we will focus on age-dependent differences in the previously described resistance mechanisms to the treatment and discuss the development of potential combination treatment strategies for enhancing the anti-tumor efficacy of anti-PD1 or PDL1 treatment in young melanoma patients.