Abstract
We evaluated patients in whom the tumor-bearing organ could not be identified in spite of surgery and biopsy. Cases in which the primary lesions were unclear at the time of surgery or which were diagnosed differently at the time of surgery and autopsy accounted for 2.1% of 932 tumor cases. Organs found to have primary lesions at the time of autopsy were: lung in 6 cases, stomach in 5, liver in 3, ovary in 2 and prostate in 2. Primary lesions in the lung were falsely diagnosed as metastatic lesions in all of the lung cancer cases, while metastatic lesions were misdiagnosed as primary lesions in all of the primary gastric cancer cases.
When cellular proteins from normal colon, normal liver, colon cancer, hepatocellular carcinoma and colon cancer metastatic to the liver were analysed by two-dimensional electrophoresis, cellular proteins from the metastatic lesions were found to possess some of the characteristics of the organs from which the tumors arose, suggesting that metastatic tissues possibly retain some of the characteristics of the organs bearing primary lesions. These results suggest that the analysis of cellular proteins can be of help in identifying organs bearing primary tumors.
