ABSTRACT
Itch is the most common chief complaint in patients visiting dermatology clinics and is analogous to cough and also sneeze of the lower and upper respiratory tract, all three of which are host actions trying to clear noxious stimuli. The pathomechanisms of these symptoms are not completely determined. The itch can originate from a variety of etiologies. Itch originates following the activation of peripheral sensory nerve endings following damage or exposure to inflammatory mediators. More than one sensory nerve subtype is thought to subservepruriceptive itch which includes both unmyelinated C-fibers and thinly myelinated Adelta nerve fibers. There are a lot of mediators capable of stimulating these afferent nerves leading to itch. Cough and itch pathways are mediated by small-diameter sensory fibers. These cough and itch sensory fibers release neuropeptides upon activation, which leads to inflammation of the nerves. The inflammation is involved in the development of chronic conditions of itch and cough. The aim of this review is to point out the role of sensory nerves in the pathogenesis of cough and itching. The common aspects of itch and cough could lead to new thoughts and perspectives in both fields.
Subject(s)
Cough/physiopathology , Nerve Fibers, Myelinated/physiology , Nerve Fibers, Unmyelinated/physiology , Pruritus/physiopathology , Sensory Receptor Cells/physiology , Animals , Capsaicin/adverse effects , Cough/chemically induced , Histamine/adverse effects , Histamine Agonists/adverse effects , Humans , Nerve Fibers, Myelinated/drug effects , Nerve Fibers, Unmyelinated/drug effects , Neurons, Afferent/drug effects , Neurons, Afferent/physiology , Peripheral Nerves/drug effects , Peripheral Nerves/physiopathology , Pruritus/chemically induced , Sensory Receptor Cells/drug effects , Sensory System Agents/adverse effectsABSTRACT
Malignant melanoma is an oncological disease characterized by etiologic heterogeneity and it has increasing incidence and mortality in the Slovak Republic. While it is treated surgically in combination with chemotherapy, targeted therapy, and immunotherapy, malignant melanomas can ulcerate and are susceptible to infections. These are highly aggressive cancers with metastasis, and recent studies have shown the presence of mutations in RAC1, PPP6C and STK19 genes in melanoma patients. Mutations in these genes are driver mutations; important in oncogenesis and providing selective advantage to tumor cells. The aim of our study is to establish a method to detect driver mutations in formalin-fixed, paraffin embedded (FFPE) tissue DNA. We applied Sanger sequencing to detect driver somatic mutations in RAC1, PPP6C, STK19 and BRAF genes in patients with malignant melanoma. Confirmation of BRAF V600E mutation was obtained by allele-specific PCR. The BRAF V600E mutation was present in 15 of 113 patients (13.2%) and the driver mutation in 7 of 113 patients (6.2 %). Our results demonstrate that Sanger sequencing analysis detects mutations in FFPE clinical samples. The identification of these somatic driver mutations in samples with verified malignant melanomas enabled development of a molecular classification of melanomas, and our study provides evidence of diversity of novel driver mutations implicated in malignant melanoma pathogenesis. These findings could have very important implications for targeted therapy.
