Are childhood and adult medulloblastomas different? A comparative study of clinicopathological features, proliferation index and apoptotic index.
Childhood medulloblastomas have been suspected to be biologically different from adult tumors, though comparative studies are sparse in the literature. The present study aims to establish any differences or nexus in the biological characteristics between childhood and adult medulloblastomas. A total of 181 medulloblastomas were studied with respect to clinical and histological characteristics, MIB-1 labeling index (MIB-1 LI), apoptotic index (AI), ratio of apoptotic to LI, p53 and Bcl-2 protein expressions. Two-thirds (112) of the 181 medulloblastomas occurred in children (< or = 15 years) and 69 in adults (> 15 years). Childhood tumors were more commonly of classical histology and midline location while the desmoplastic variant and lateral location occurred more frequently in adults. Adult medulloblastomas were biologically less aggressive, having lower growth rate parameters (mean MIB-1 LI 19.1 +/- 15.7; AI 3.73 +/- 2.71 and AI:LI 0.207 +/- 0.162) as compared to childhood tumors (mean MIB-1 LI 28.3 +/- 20.4; AI 2.86 +/- 2.14 and AI:LI 0.108 +/- 0.111). p53 and Bcl-2 protein expressions were infrequent in all groups of tumors. No difference was noted in any of the parameters when classical and desmoplastic medulloblastomas were compared as a whole. But when compared between the age groups, an interesting observation (hitherto unreported in English literature) was that both classical and desmoplastic variants of childhood medulloblastomas had higher LI, lower AI and lower AI:LI ratio than their counterparts in adults, indicating that differences in growth rates cannot be attributed to differences in the frequency of occurrence of the histological variants in the two age groups. Thus, this study conclusively shows that there is a biological difference between childhood and adult medulloblastomas which is independent of standard histology and appeared to be associated more with age-related factors. This also warrants less-aggressive therapy for adult medulloblastoma.
Sarkar
Chitra
C
Department of Pathology, All India Institute of Medical Sciences, New Delhi. sarkarcs@hotmail.com
Pramanik
Pulakesh
P
Karak
Asis Kumar
AK
Mukhopadhyay
Partho
P
Sharma
Mehar Chand
MC
Singh
Varindera Paul
VP
Mehta
Veer Singh
VS
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000375:Aging / Q000502:physiology*; D017209:Apoptosis; D002455:Cell Division; D002528:Cerebellar Neoplasms / Q000453:epidemiology / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D015994:Incidence; D007223:Infant; D008527:Medulloblastoma / Q000453:epidemiology / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D017678:Sex Distribution; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53