CORRELATION OF MYCN AMPLIFICATION, TRK-A AND CD44 EXPRESSION WITH CLINICAL STAGE IN 250 PATIENTS WITH NEUROBLASTOMA

In contrast to MYCN amplification, expression of either trk-A or CD44 in neuroblastoma is a favourable prognostic factor and were therefore investigated in tumours from 250 patients. One hundred and eleven loca lised/4s (Group 1) and 139 stage 4 (Group 2) tumours were analysed. MY CN copy number was obtained by Southern blotting or PCR amplification and was detected in 28 stage 4 tumours. Trk-A and CD44 expression was detected by immunoperoxidase staining using murine monoclonal antibodi es 5C3 and L178, respectively. Expression was scored as positive (homo geneous), mixed (heterogeneous) or non-reactive (negative). Trk-A expr ession was found in 95% of Group 1 tumours and 49% of Group 2 tumours. CD44 expression was found in 100% of Group 1 tumours, the majority of which had a strong homogeneous expression. Lack of CD44 expression oc curred in 25% of tumours, all stage 4 neuroblastoma. Of the 28 MYCN am plified tumours, 27/28 (96%) were trk-A negative, and 13/28 (46%) CD44 negative. We conclude that (1) a significant percentage of stage 4 ne uroblastoma express either or both trk-A and CD44, (2) the absence of CD44 expression is highly restricted to stage 4 neuroblastoma and is a ssociated with the lack of trk-A expression, (3) trk-A negativity amon g CD44-positive tumours is associated with stage 4 neuroblastoma and ( 4) the absence of trk-A expression is highly correlated with MYCN ampl ification. (C) 1997 Elsevier Science Ltd.