Two different types of cell loss patterns of murine tumors and their corresponding histological findings and possible mechanisms of production of hypoxic cells.
Cell loss patterns of five tumors and their histological findings were investigated in WHT/Ht strain mice. The tumors investigated were squamous cell carcinoma H, squamous cell carcinoma NOS, squamous cell carcinoma TAK, rhabdomyosarcoma KAS, and fibrosarcoma YAS. The present study revealed that histological findings of tumor tissues are not necessarily corded structure presented by Thomlinson and Gray. The five were divided into two groups according to their histological findings, i.e. a corded structure (squamous carcinoma H and NOS) and a non-corded structure (squamous cell carcinoma TAK, rhabdomyosarcoma KAS and fibrosarcoma YAS). The cell loss patterns (125I-iododeoxyuridine retention curves) were also divided into two groups which corresponded to the histological structures. Two tumors with the corded structure (squamous cell carcinoma H and NOS) have a cell loss pattern with a constant shoulder portion (a migration time of tumor cells through a tumor cord from capillary to necrotic region). In these tumors, the cell loss occurred in the necrotic regions. In the other tumors with the non-corded structure, cell loss curves have no constant shoulder portion and cell loss might occur throughout the tumor. The origin of hypoxic cells in these two types of histology are presumably different. The diffusion-limited hypoxia, i.e. chronically hypoxic cells, may be the main cause for the tumors with corded structure. On the other hand, hypoxia as a result of temporary cessation of blood flow within the tumor vasculature, i.e. acutely hypoxic cells, may mainly occur in the tumor with non-corded structure.
Department of Radiation Biophysics, Faculty of Medicine, University of Tokyo, Japan.
Y
Y
Takai
K
K
Sakamoto
S
S
Okada
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000503:physiopathology*; D015687:Cell Hypoxia / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D005260:Female; D005354:Fibrosarcoma / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D012208:Rhabdomyosarcoma / Q000473:pathology / Q000503:physiopathology*