Indeed, it is indicated that cytotoxic ALCL cases may be either p80/ALK positive or negative, suggesting that the cytotoxicity and expression of p80/ALK are independent phenomena among the cases of ALCL of T- and null-cell type.     ///    "However, these features are shared, though to a lesser degree, by other p80/ALK-negative lymphoid neoplasms. "    ///    "Recently, some investigators including us asserted that these p80NPM/ALK or ALK1-positive(p80/ALK+) ALCLs represent a distinct genetic entity with occurrence in young patients and a favorable prognosis, and should be differentiated from the p80/ALK- tumors with the relatively aggressive clinical course. "