1994 Fiscal Year Final Research Report Summary
Analysis of the mechanism of lymph node metastasis of oral carcinomas
| Project/Area Number |
04454497
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
外科・放射線系歯学
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| Research Institution | Niigata University |
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Principal Investigator |
NAKAJIMA Tamio School of Dentistry Professor, 歯学部, 教授 (10014010)
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| Co-Investigator(Kenkyū-buntansha) |
HAMAMOTO Yoshioki School of Dentistry Assistant Professor, 歯学部, 助手 (40231526)
NOMURA Tsutomu Dental Hospital Assistant Professor, 歯学部・附属病院, 助手 (20228365)
SHINGAKI Susumu School of Dentistry Associate Professor, 歯学部, 助教授 (30134943)
SAKU Takashi School of Dentistry Professor, 歯学部, 教授 (40145264)
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| Project Period (FY) |
1992 – 1994
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| Keywords | Oral carcinoma / Lymph node metastasis / Basement membrane / Lymphatic invasion / Flow cytometry |
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| Research Abstract |
The mechanism of lymph node metastasis of oral carcinomas was studied using human oral carcinomas and an animal model of squamous cell carcinoma with a high metastatic potential to lymph nodes in hamsters.
Flow cytometric analysis of 90 fresh and 96 paraffin-embedded tissue samples of oral carcinomas showed that although the incidence of aneuploidy in primary tumors with metastasis was higher than those without metastasis, there was na evident tendency to a shift down to diploidy at metastatic lymph nodes. The results indicate that the chance of evolution of metastatic cell lines is higher in aneuploid tumors than in diploid tumors, possibly because the former are more heterogenous ; however, most cell lines responsible for causing lymph node metastasis are diploid.
An analysis of basement membrane formation around tumor nests of 0-1N during the process of lymph node metastasis showed that with the decrease of tumor nest size, the disruption of basement membrane became conspicuous, in particular ato the invasion front. The findings suggest that the disappearance of besement membrane associated with reduction in size of tumor nests is an essential sign for local invasion of tumor cells leading to lymphatic invasion and metastasis to regional lymph nodes. The growth of the tumor was accompanied by a proliferation of abundant dilated lymphatic vessels which contained clusters of tumor cells. On serial sections, these clusters were in continuity with adjacent tumor nests, indicating that the key step of lymph node metastasis is direct invasion of lymphatic vessels by tumors cells which may differ from the way of hematogenous metastasis.
Stromal reactions studied in human oral carcinomas showed a similarity between primary and metastatic sites, indicaintg that the tumor has its own potency to induce its specifec stroma.
The results of this research were reported in international journals and meetings.
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