Association of expression between N‐myc gene and major histocompatibility complex class I gene in surgically resected human neuroblastoma

Amplification of the N‐myc gene in neuroblastoma correlates with advanced stage and poor prognosis. Association of the expression between N‐myc and major histocompatibility complex (MHC) class I genes in 33 neuroblastomas obtained from Japanese children was investigated. Amplification of the N‐myc gene was observed in two of five cases in Stage III, six of 11 cases in Stage IV, and one of five cases in Stage IV‐S. In each case, the expression of N‐myc gene was significantly increased. The expression was also increased in cases without amplification of the N‐myc gene, the origin being from the suprarenal region. Expression of the MHC class I gene was significantly decreased in five of these nine with a high level of N‐myc expression with amplification. These results suggest that the down‐modulation of the MHC class I expression may be associated with the high level of expression and amplification of N‐myc gene in the advanced stage of neuroblastoma.