Clonality in Langerhans' cell histiocytosis

Abstract

EDITOR,—Finbarr E Cotter and Jon Pritchard rightly state that the finding of clonality in Langerhans' cell histiocytosis might provide “the first solid clue to defining the aetiology of the condition in 100 years.”1 As Langerhans' cell histiocytosis is probably a clonal neoplastic disorder2 the occurrence of both localised (meaning strictly localised to the bone) and disseminated forms as well as both non-familial and familial cases suggests that it may arise by a two step mutational process, similar to that in the development of retinoblastoma. The two mutation hypothesis was first formulated in …