Response of patients with indolent systemic mastocytosis to tamoxifen citrate

Mastocytosis and Skin Cancer: The Current State of Knowledge

Mastocytosis is a heterogeneous group of diseases associated with excessive proliferation and accumulation of mast cells in different organs. Recent studies have demonstrated that patients suffering from mastocytosis face an increased risk of melanoma and non-melanoma skin cancer. The cause of this has not yet been clearly identified. In the literature, the potential influence of several factors has been suggested, including genetic background, the role of cytokines produced by mast cells, iatrogenic and hormonal factors. The article summarizes the current state of knowledge regarding the epidemiology, pathogenesis, diagnosis, and management of skin neoplasia in mastocytosis patients.

Mast Cell Clonal Disorders: Classification, Diagnosis and Management

Mast cell clonal disorders are characterized by the clonal proliferation of pathological mast cells as a result of somatic mutations in the KIT gene, most commonly the D816V mutation. Accumulation and degranulation of these cells causes a wide variety of symptoms. Mast cell clonal disorders can be divided into mastocytosis and monoclonal mast cell activation syndrome, depending of the level of clonality. The severity of mastocytosis varies from an indolent variant with a good prognosis, to an aggressive condition with short life expectancy. Diagnosis is based on demonstration of clonality and accumulation in the skin and in extracutaneous tissues. Treatment is highly individualized, and is based on the severity of the condition. Treatment of patients with indolent systemic mastocytosis is aimed at reducing symptoms, using histamine H1 and H2 receptor antagonists as a starting point. In addition, associated conditions such as osteoporosis must be treated. Treatment of advanced systemic mastocytosis is aimed at reducing mast cell load through cytoreductive therapy. The choice of such therapy depends on the KIT mutational status. Though currently there is no curative treatment available, promising new therapies such as midostaurin are emerging that have demonstrated success in reducing symptoms and improving quality of life.

New Developments in Mast Cell Biology: Clinical Implications

Mast cells (MCs) are present in connective tissue and at mucosal surfaces in all classes of vertebrates. In health, they contribute to tissue homeostasis, host defense, and tissue repair via multiple receptors regulating the release of a vast stockpile of proinflammatory mediators, proteases, and cytokines. However, these potentially protective cells are a double-edged sword. When there is a repeated or long-term stimulus, MC activation leads to tissue damage and dysfunction. Accordingly, MCs are implicated in the pathophysiologic aspects of numerous diseases covering all organs. Understanding the biology of MCs, their heterogeneity, mechanisms of activation, and signaling cascades may lead to the development of novel therapies for many diseases for which current treatments are lacking or are of poor efficacy. This review will focus on updates and developments in MC biology and their clinical implications, with a particular focus on their role in respiratory diseases.

Pharmacological treatment options for mast cell activation disease

Mast cell activation disease (MCAD) is a term referring to a heterogeneous group of disorders characterized by aberrant release of variable subsets of mast cell (MC) mediators together with accumulation of either morphologically altered and immunohistochemically identifiable mutated MCs due to MC proliferation (systemic mastocytosis [SM] and MC leukemia [MCL]) or morphologically ordinary MCs due to decreased apoptosis (MC activation syndrome [MCAS] and well-differentiated SM). Clinical signs and symptoms in MCAD vary depending on disease subtype and result from excessive mediator release by MCs and, in aggressive forms, from organ failure related to MC infiltration. In most cases, treatment of MCAD is directed primarily at controlling the symptoms associated with MC mediator release. In advanced forms, such as aggressive SM and MCL, agents targeting MC proliferation such as kinase inhibitors may be provided. Targeted therapies aimed at blocking mutant protein variants and/or downstream signaling pathways are currently being developed. Other targets, such as specific surface antigens expressed on neoplastic MCs, might be considered for the development of future therapies. Since clinicians are often underprepared to evaluate, diagnose, and effectively treat this clinically heterogeneous disease, we seek to familiarize clinicians with MCAD and review current and future treatment approaches.