Tzortzatou-Stathopoulou F, Mikraki V, Xaidara A, Moschovi M, Evangelinos V, Panagopoulos K
First Department of Paediatrics, University of Athens, Aghia Sophia Children's Hospital, Goudi, Greece.
Pediatr Hematol Oncol. 1996 Nov-Dec;13(6):511-9. doi: 10.3109/08880019609030866.
The activity of the enzymes 5-formyl tetrahydrofolate cyclodehydrase and 5,10-methenyl tetrahydrofolate cyclohydrolase has been studied cytochemically in children's primary brain tumors. These enzymes play a significant role in purine biosynthesis. Thirty children, aged 1-12 years, were studied, 12 with medulloblastoma, 14 with glioma grade I-IV, and 4 with ependymoma. The activity of the enzymes was apparent as cytoplasmic granules that sometimes overlie the nucleus of the tumor cells. This coincidence showed that different types of brain tumors exhibit different degrees of enzymic activity, which in some cases correlated positively with the malignant potential of the tumor. Approximately one third of the cases were negative for any activity of these enzymes. The intensity of the staining of 5,10-methenyl tetrahydrofolate cyclohydrolase activity was actually higher than that of 5-formyl tetrahydrofolate cyctodehydrase. The clinical or prognostic significance of these findings remains to be clarified, but we believe that cylochemistry provides a sensitive technique for the detection, localization, and description of these enzymes in brain tumor cells. A clear understanding of the mode of action of these enzymes may contribute to devising novel therapeutic strategies.
在儿童原发性脑肿瘤中，已采用细胞化学方法研究了5-甲酰四氢叶酸环化脱水酶和5,10-亚甲基四氢叶酸环水解酶的活性。这些酶在嘌呤生物合成中起重要作用。研究了30名年龄在1至12岁的儿童，其中12例为髓母细胞瘤，14例为I-IV级胶质瘤，4例为室管膜瘤。酶的活性表现为细胞质颗粒，有时覆盖肿瘤细胞的细胞核。这种巧合表明，不同类型的脑肿瘤表现出不同程度的酶活性，在某些情况下，这与肿瘤的恶性潜能呈正相关。约三分之一的病例这些酶的任何活性均为阴性。5,10-亚甲基四氢叶酸环水解酶活性的染色强度实际上高于5-甲酰四氢叶酸环化脱水酶。这些发现的临床或预后意义仍有待阐明，但我们认为细胞化学为检测、定位和描述脑肿瘤细胞中的这些酶提供了一种灵敏的技术。清楚了解这些酶的作用方式可能有助于制定新的治疗策略。
