Changes to the Summary (01/30/2015)
The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.
Added text to state that regardless of having a BRAF V600E mutation, nearly all lesions have been reported to show evidence of activated extracellular signal-regulated kinase (ERK) downstream of BRAF; therefore, other mutations in genes that are part of the RAS-RAF-MEK-ERK pathway might also be identified. This has been shown with activating mutations involving the CSF-1 receptor, RAS, and MAP2K1 (MEK) for a significant percentage of BRAF V600E–negative specimens (cited Chakraborty et al. as reference 5).
Added text to state that a subset of adult pulmonary LCH patients appeared to be clonal. An analysis of BRAF mutations showed that a significant proportion of patients have evidence for mutant BRAF V600E, which has a statistically significant association with cigarette smoking (cited Roden et al. as reference 17).
Added text about MAP2K1 mutations and ERK activation in LCH patients (cited Chakraborty et al. and Brown et al. as references 22 and 23, respectively).
Added text to state that liver biopsy may be the only way to distinguish active LCH from end-stage fibrosis.
Added text to state that pulmonary LCH can be diagnosed by bronchoscopy in about 50% of adult patients, as defined by characteristic CD1a immunostaining cells of greater than or equal to 5% of cells observed (cited Baqir et al. as reference 11).
Added text to state that BRAF V600E mutations have been demonstrated in pulmonary LCH lesions in adults, suggesting a clonal process in a significant proportion of patients (cited Roden et al. as reference 13).
This summary is written and maintained by the PDQ Pediatric Treatment Editorial Board, which is editorially independent of NCI. The summary reflects an independent review of the literature and does not represent a policy statement of NCI or NIH. More information about summary policies and the role of the PDQ Editorial Boards in maintaining the PDQ summaries can be found on the About This PDQ Summary and PDQ NCI's Comprehensive Cancer Database pages.