ヒト脳腫瘍におけるc-myc遺伝子産物の検索

IMMUNOHISTOCHEMICAL STUDY OF C-MYC ONCOGENE PRODUCT IN HUMAN BRAIN TUMORS

　抄録　c-myc遺伝子は真核細胞に広く検出され，細胞の増殖や分化に重要な役割を演じているものと考えられている。この遺伝子はいく種かの癌細胞においてしばしば発現の交進が認められており，これと臨床的悪性度との関連が示唆される例もある。この遺伝子の発現は脳腫瘍の生物学的特性を解析するうえでも重要であると考え，各種脳腫瘍におけるその発現を産生蛋白に対するモノクローナル抗体を用いて免疫組織化学的に検討した。その結果，c-myc産物はastrocytoma系腫瘍に広く認められるが，grade 2の例に比べ悪性度の高いgrade 3や4の例では核が強陽性を示す細胞が多数出現した。しかしgrade 3例に比しgrade　4例ではこれはむしろ減弱する傾向がみられた。Meningiomaやneurinomaなど非グリオーマ系腫瘍では核陽性細胞は乏しいが，neurinomaの一部の例では比較的多数認められた。

C-myc oncogene is widely distributed in eukaryo-tic cells and is supposed to play an important role in the cellular proliferation and differentiation. Enhanced expression of this oncogene is reported in many kind of tumors, which is often associated with increased malignancy. It seems, therefore, important to study the expression of this oncogene in analyzing the cell biologic features of brain tumors. In the present paper we investigated the distribution of this oncogene product in paraffin-embedded tissue of various kind of brain tumors with a monoclonal antibody to synthetic c-myc peptide. The results demonstrated that c-myc product was detectable in most of the astrocytoma linage. The immunoreaction within the cell nuclei was more intense in grade 3 and grade 4 astrocyto-mas than in grade 2 tumors. The expression in grade 4 tumors was, however, rather weaker that in grade 3 tumors. In benign, non-glial tumors like meningiomas and neurinomas, the nuclear immunoreaction was usually absent or only weak, althouth it was enhanced in a case of acoustic and spinal neurinomas associated with von Reck-linghausen's disease.