CCL17 and classic Hodgkin lymphoma: cHL cells secrete cytokines/chemokines and express a variety of cytokine/chemokine receptors [8, 47] and it is now widely assumed that the clinical and histological features of cHL are primarily due to the effects of a plethora of cytokines and chemokines secreted by cHL cells such as CCL5 [48, 49], CCL17 [47], CCL22 [50], CCL28 [51], and CCL20 [39, 52] or by the surrounding cellular infiltrate.