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사람의 위암 조직을 미세구조와 metalothionein(MT)에 대한 면역 조직 및 세포화학적 방법으로 조사하였던 바, 다음과 같은 결과를 얻어냈다. 위암 세포들은 핵 세포질비가 정상세포에 비해 크고, 불규칙한 핵과 이질염색질의 분포가 증가하였으며, 세포질내에서 유리리보솜의 분포가 뚜렷이 증가하였다. 면역 조직 및 세포화학적 방법으로 MT의 발현을 조사하였던 결과, 이 단백질은 위암조직의 암세포에서 반응성이 높게 나타났으며, 주로 핵 부위에 집중되는 경향을 보였으며, 특히 이질염색질과 인 부위에서 면역 금 입자들이 주로 분포하는 것으로 관찰되었다. 이러한 결과들은 위암 세포의 미세구조가 미분화세포들이 나타내는 일반적인 특징과 비교되었으며, 위암 세포에서 MT가 증가하는 현상은 이 단백질이 세포질에서 합성되어 핵내로 수송된 후, 세포 증식을 위한 전사과정에 관여할 것임을 시사하는 것이다.


Metallothionein (MT) is a family of ubiquitous, low molecular weight (6,000-7,000D), cysteine-rich (30-35%) inducible protein with a high affinity to metal ions and has no aromatic amino acids and histidine. Some of the known functions of MT include detoxification of heavy metals and alkylating agents and neutralization of free radicals. Also, this protein has been reported to involve in tumor pathophysiology and therapy resistance. MT expression may affect a number of cellular processes including gene expression, apoptosis, proliferation and differentiation. Many reports on the physiological and biochemical properties of MT have been published, but ultrastructural reports on the localization of MT in human gastric cancer tissues are extremely rare. The present study was undertaken to examine the ultrastructural features and the localization of MT within the gastric adenocarcinoma. Ultrastructures of gastric cancer cells were characterized by the high nuclear cytoplasmic ratio, the interdigitation between cells, the irregular nucleus containing much heterochromatin and the wide distribution of free ribosomes in the cytoplasm. Immunohistochemical reaction for MT was prominent in the gastric adenocarcinoma. And the immunogold labellings were more prominent within the nucleus than the cytoplasm. Particularly, immunogold particles were numerously seen at nulcleolus or nucleolar associated heterochromatin. These results suggest that MT expression by gastric cancer cells is associated with cell proliferative activity and is possibly synthesized in the cytoplasm, and then the protein is transported into the nucleus to participate any transcriptional steps.