Drug targets and predictive biomarkers in the management of metastatic melanoma

Patient-derived tumor xenograft models for melanoma drug discovery

INTRODUCTION

Cutaneous metastatic melanoma (MM) is an aggressive form of skin cancer, with treatment providing cures to a minority of patients. The multiple risk factors that contribute to MM development suggest that cutaneous melanomas embody a repertoire of altered genetic events requiring studies to better understand its biology in order to develop novel therapies.

AREAS COVERED

Patient-derived tumor xenograft (PDTX) mouse models are noted to be superior for novel drug discovery and tumor biology studies due to their ability to maintain tumor heterogeneity and their use as real-time individualized patient models. In this review, the authors highlight the utility of PDTX models in advancing treatment options for patients with MM by creating invaluable preclinical models that exhibit patient-relevant treatment outcomes.

EXPERT OPINION

There is a strong necessity to reassess current approaches in which preclinical experiments are designed and executed in order to minimize unwarranted clinical trials. With rigorously performed preclinical studies, PDTX models have the capability to effectively confirm or deny drug effective outcomes. The ability to do this, however, will demand better aids to guide experimental design, the redefining of preclinical efficacy, and the understanding that these models should be viewed as complementary to other drug prediction and efficacy tools.

Is oestrogen an important player in melanoma progression?

The oestrogen-dependent regulation of cell behaviour is realised by stimulation of specific oestrogen receptors. The classical oestrogen receptors ERα and ERβ are transcription factors, and they modulate expression of hormonally regulated genes, while the third one, GPER, is thought to be responsible for the observed rapid, non-genomic cellular response. Oestrogen dependency is attributed to a number of cancers, including breast, ovarian and endometrial cancer; however, there is still growing evidence that melanoma should also be cited as a hormonally dependent tumour. This comes from the observations of gender-related differences in melanoma progression and reports concerning the history of the malignant course of melanomas during pregnancy. Although, the observations of oestrogen regulation of melanoma progression are controversial, the effect of oestrogen should not be neglected, as the skin possesses its own hormonal microenvironment. This aspect of melanoma progression should be taken under careful consideration as it may offer new therapeutic possibilities.

Immunomics in Skin Cancer - Improvement in Diagnosis, Prognosis and Therapy Monitoring

This review will focus on the elements of the skin’s immune system, immune cells and/or non-immune cells that support immune mechanisms, molecules with immune origin and/or immune functions that are involved in skin carcinogenesis. All these immune elements are compulsory in the development of skin tumors and/or sustainability of the neoplastic process. In this light, recent data gathered in this review will acknowledge all immune elements that contribute to skin tumorigenesis; moreover, they can serve as immune biomarkers. These immune markers can contribute to the diagnostic improvement, prognosis forecast, therapy monitoring, and even personalized therapeutical approach in skin cancer. Immune processes that sustain tumorigenesis in non-melanoma and melanoma skin cancers are described in the framework of recent data.