Anti-apoptotic and growth-promoting markers in adult medulloblastomas

the aim of this study was to investigate the pathologic features, proliferation potential and expression of some anti-apoptotic and growth-promoting markers in adult medulloblastomas.

we analyzed the immunohistochemical expression of survivin, c-KIT, Bcl-2, fascin, p-53 and Ki-67 in 18 adult medulloblastomas (> 16 years of age).

study included 14 males and 4 females (mean age: 22.9 ± 8.2). 14 cases were classical, 2 desmoplastic/nodular and 2 large cell medulloblastomas. Moderate-to-high nuclear survivin expression was observed with high percentages (55 - 100%) in all medulloblastomas while Bcl-2 was mildly positive in only 1 case. Interestingly, mild-to-moderate cytoplasmic c-KIT expression was demonstrated in 16 cases (89%) without membranous accentuation. Fascin expression was observed in 13 medulloblastomas (72%), 9 of which showing moderate to high immunoreactivity. Mild p53 expression was present in only 4 cases (22%). Mean Ki-67 index was 20.6% (range 8 - 55%).

frequent nuclear survivin expression implies the predominance of anti-apoptotic factors in pathogenesis of adult medulloblastomas. It may also be a potential therapeutic target for adult medulloblastomas. Although Blc-2 immunoreactivity was previously reported in approximately 30% in medulloblastomas, we have observed that it is rarely expressed in the present series of adult medulloblastomas. To our knowledge, this is the first study evaluating fascin expression in medulloblastomas. Its presence may be related to the neuronal differentiation. Mild-to-moderate cytoplasmic c-KIT immunoreactivity without membranous staining in adult medulloblastomas may support the previous studies reporting low level of c-KIT protein expression with lack of activating mutations in medulloblastomas. It seems p53 is rarely involved in the course of develepment of adult medulloblastomas.