Degeneration of saccular hair cells caused by MITF gene mutation
NEURAL DEVELOPMENT
Authors: Du, Yi; Ren, Li-li; Jiang, Qing-qing; Liu, Xing-jian; Ji, Fei; Zhang, Yue; Yuan, Shuo-long; Wu, Zi-Ming; Guo, Wei-Wei; Yang, Shi-Ming
Abstract
BackgroundWaardenburg syndrome (WS) is the consequence of an inherited autosomal dominant mutation which causes the early degeneration of intermediate cells of cochlear stria vascularis (SV) and profound hearing loss. Patients with WS may also experience primary vestibular symptoms. Most of the current WS studies did not discuss the relationship between WS and abnormal vestibular function. Our study found that a spontaneous mutant pig showed profound hearing loss and depigmentation. MITF-M, a common gene mutation causes type WS which affect the development of the intermediate cell of SV, was then identified for animal modeling.ResultsIn this study, the degeneration of vestibular hair cells was found in pigs with MITF-M. The morphology of hair cells in vestibular organs of pigs was examined using electron microscopy from embryonic day E70 to postnatal two weeks. Significant hair cell loss in the mutant saccule was found in this study through E95 to P14. Conversely, there was no hair cell loss in either utricle or semi-circular canals.ConclusionsOur study suggested that MITF-M gene mutation only affects hair cells of the saccule, but has no effect on other vestibular organs. The study also indicated that the survival of cochlear and saccular hair cells was dependent on the potassium release from the cochlear SV, but hair cells of the utricle and semi-circular canals were independent on SV.
Immunohistochemical analysis of Bcl-2, nuclear S100A4, MITF and Ki67 for risk stratification of early-stage melanoma - A combined IHC score for melanoma risk stratification
JOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT
Authors: Jurmeister, Philipp; Bockmayr, Michael; Treese, Christoph; Stein, Ulrike; Lenze, Dido; Joehrens, Korinna; Friedling, Franziska; Dietel, Manfred; Klauschen, Frederick; Marsch, Wolfgang; Fiedler, Eckhard; von Laffert, Maximilian
Abstract
Background and objectives: Overall survival (OS) in patients with early-stage malignant melanoma differs. To date, there are no established prognostic markers. We aimed to contribute to a better understanding of potential prognostic immunohistochemical markers for risk stratification. Patients and methods: 161 surgically resected early-stage malignant melanomas (stage pT1 and pT2) were analyzed for expression of 20 different proteins using immunohistochemistry. The results were correlated with OS. The cohort was randomly split into a discovery and a validation cohort. Results: High Bcl-2 expression, high nuclear S100A4 expression as well as a Ki67 proliferation index of >= 20 % were associated with shorter OS. Strong MITF immunoreactivity was a predictor for favorable prognosis. A combination of these four markers resulted in a multi-marker score with significant prognostic value in multivariate survival analysis (HR: 3.704; 95 % CI 1.484 to 9.246; p = 0.005). Furthermore, the score was able to differentiate a low-risk group with excellent OS rates (five-year survival rate: 100 %), an intermediate-risk group (five-year survival rate: 81.8 %) and a high-risk group (five-year survival rate: 52.6 %). The prognostic value was confirmed within the validation cohort. Conclusions: Combined immunohistochemical analysis of Bcl-2, nuclear S100A4, Ki67 and MITF could contribute to better risk stratification of early-stage malignant melanoma patients.