1992 年 25 巻 5 号 p. 583-590
We have previously reported that abnormal accumulation of p53, an onco-suppressor gene product, is immunohistologically demonstrable in microwave (MW)-fixed, paraffin-embedded sections of colorectal tumors with the use of a monoclonal antibody, PAb1801 (Am. J. Clin. Pathol., 97: 244-249, 1992). This monoclonal antibody targets the human specific epitope of p53 molecule but cannot distinguish the mutant form from wild-type p53, and no immunoreactivity of a mutant-specific monoclonal antibody, PAb240, could be observed in MW-fixed sections. In the present paper, we have executed a comparative immunohistochemical study on p53 and 70Kd heat shock proteins (HSP70) in MW-fixed sections of 20 colorectal carcinomas and 20 adenomas because mutant p53 has been reported to form a stable complex with HSP70. The use of PAb1801 resulted in nuclear p53 being detected in 11 out of 20 carcinomas and p53 being expressed focally in five out of 20 adenomas. In the adjacent sections, the majority of p53-positive carcinomas and adenomas also expressed HSP70 in the nucleus as well as in the cytoplasm. Coincident expression of p53 and HSP70 in the nuclei of colorectal tumor cells implies that the p53 detected with PAb1801 may be the mutated protein that forms stable complexes with HSP70.
