In view of the recent reports describing the expression of CSF1R protein in cell lines [24] and CSF1R mRNA in tumour cells of cHL cases [23], double immunoenzymatic and immunofluorescence labelling studies were also performed in cHL tumours (Fig 4A), showing that CD30+ HRS cells lack detectable CSF1R. This evidence concerns the gene TNFRSF8 and classic Hodgkin lymphoma.