Journal of Clinical & Experimental Pathology
Open Access

Abstract

Langerhans cell histiocytosis (LCH) is a clinically and histologically heterogeneous disorder, characterized by a reactive clonal proliferation and accumulation of CD1a+/CD207+ dendritic cells in inflammatory lesions. Recurrent BRAFV600E and MAP2K1 mutations have been reported in LCH. To investigate the relationship between the mutation, clinical findings and differentiation status of LCH respectively, we studied 97 cases of LCH using Sanger sequencing and immunohistochemistry. The mutually exclusive BRAFV600E and MAP2K1 mutation rates were 32% and 17.5%, respectively. All MAP2K1 mutations were missense mutations without any in-frame deletions, two new recurrent missense mutations (i.e., p.E38K and p.P105S) were also found. More BRAFV600E and MAP2K1 mutations occurred in underage patients compared to adult patients and were correlated with relapse. To the differentiation related markers, the BRAF/MAP2K1-mut LCH expressed CD14 but rarely expressed CD83 or CD86 (p<0.001). On the contrary, BRAF/MAP2K1-wt LCH cells rarely expressed CD14 but expressed CD86 and some cells also expressed CD83+ (p<0.001). This indicates that the BRAF/MAP2K1-mut LCH cells had a more immature state than BRAF/MAP2K1-wt LCH cells. Moreover, we also found the BRAFV600E and MAP2K1 mutations were significantly associated with pERK expression (p<0.001). Therefore, the RAS/ RAF/MEK/ERK pathway might play a more important role in LCH in underage patients than in adult patients.

Biography

Ying Guo has completed her MD from Shanxi Medical University and PhD from Fourth Military Medical University. She is an Associate Professor of Department of Pathology of Fourth Military Medical University. She has published more than 20 international papers and 40 Chinese papers in reputed journals.

Email: guoying@fmmu.edu.cn