PROLIFERATION AND APOPTOSIS IN NEUROBLASTOMA - SUBDIVIDING THE MITOSIS-KARYORRHEXIS INDEX

The Shimada classification is a frequently used, histopathological cla ssification system for neuroblastoma tumours. Tumours are classified a s prognostically favourable or unfavourable based upon stroma content, degree of neuroblastic maturation and patient age at diagnosis. The m itosis-karyorrhexis index is introduced in this classification system, as the cellular density sum of mitotic and karyorrhectic cells in the tumour. The biological nature of karyorrhectic cells is uncertain, bu t a high mitosis-karyorrhexis index in stroma-poor tumours is an indic ator of poor prognosis. In this study, neuroblastoma tumours were anal ysed for cell proliferation, using antiproliferating cell nuclear anti gen (PCNA) immunohistochemistry, and apoptosis, by morphology and in s itu end-labelling of fragmented DNA. The karyorrhectic cells described in the Shimada classification were shown to be either proliferating o r undergoing apoptosis. It is further shown that a high cellular densi ty of proliferating cells correlates with poor prognosis, whereas a hi gh density of apoptosis, in contrast, indicates favourable outcome.