THE 1P DELETION IS NOT A RELIABLE MARKER FOR THE PROGNOSIS OF PATIENTS WITH NEUROBLASTOMA

Human neuroblastoma cells often have deletions of the distal short arm of chromosome 1 (Ip), Earlier studies using chromosome analysis had s uggested that the Ip deletion is correlated with a poor survival chanc e for the patient. We have reevaluated this possibility by analyzing 5 1 neuroblastomas for loss of heterozygosity (LOH) at Ip, We detected L OH in 32% of the cases, LOH did not correlate with the age of the pati ents at diagnosis or with tumor stage but was correlated significantly with amplification of the MYCN proto-oncogene. Nine of 10 MYCN-amplif ied tumors had deletions in Ip (P < 0.001), Survival chances of patien ts with tumors carrying MYCN amplification together with the deletion al Ip were decreased significantly (eight of nine affected patients di ed) compared with a patient group without any of these aberrations (P < 0.001), However, the deletion of Ip alone without MYCN amplification was not associated with a poor outcome compared with patients who had neither deletion nor amplification (only two of eight affected patien ts died; P = 0.803), From these data we conclude that Ip deletions are not reliable markers to determine a patient's prognosis, They may, ho wever, identify a subgroup of neuroblastomas in which MYCN is amplifie d readily, resulting in rapid tumor progression.