Young-Chi Kim

Significance of 2-3 and 2-6 sialylation of lewis A antigen in pancreas cancer

Distributions of sialylated derivatives of Lewis a (Lea) antigen in cancer tissue of the human pancreas and in the sera of patients with pancreas diseases have been studied; the significance of 2‐3 and 2‐6 sialylation of Lea antigens in pancreas cancer have been investigated using specific monoclonal antibodies. In most pancreas cancer tissue the 2‐3 sialylated Lea antigen was found to be specifically distributed in cancer cells as determined by immunohistologic techniques, while a significantly smaller amount of the antigen was detected in surrounding nonmalignant pancreas tissue, which was infiltrated by cancer cells. Conversely, the 2‐6 sialylated Lea antigen was abundantly present in nonmalignant pancreas tissue, while it was less frequently present in pancreas cancer cells. When the sera of 66 patients with pancreas diseases were examined for these sialylated Lea antigens, correlation studies showed that the levels of 2‐3 sialylated Lea tended to be 44.1 times more than the levels of 2‐6 sialylated Lea in the sera of cancer patients. The average ratio of 2‐3 sialylated Lea to 2‐6 sialylated Lea was 0.23 in the sera of patients with pancreatitis. These data collectively indicate that the 2‐3 sialylation of Lea is remarkably enhanced, and the 2‐6 sialylation of Lea antigen is suppressed in pancreas cancer. The determination of the 2‐3 sialylated Lea to 2‐6 sialylated Lea ratio in patients with pancreas diseases may be helpful for the differential diagnosis of pancreas cancer and nonmalignant pancreatic disorders.

Expression of epithelial markers in sarcomatoid carcinoma: an immunohistochemical study.

Thirty‐four cases of sarcomatoid carcinoma with minimal epithelial components (SC) and six cases of sarcomatous tumour without any epithelial component (ST) in various organs were studied by the immunoperoxidase technique for the expression of epithelial markers, cytokeratins and epithelial membrane antigen (EMA). Employing antibodies against both high and low molecular weight cytokeratins, sarcomatoid components in 30 examples of SC were stained positively. Epithelial membrane antigen was demonstrated in 19 out of 34 SC. The positive cells for epithelial markers within sarcomatoid components in some cases of SC, which were regarded as originating from squamous cell carcinoma, tended to be seen less frequently than in the tumours derived from adenocarcinoma or transitional cell carcinoma. In six cases of ST, stain for EMA was negative and stain for cytokeratins was positive in three examples. The immunohistochemical examination of epithelial markers in the tumours of these types may be of value in differentiating these tumours from true sarcomas.

Unusual renal sarcoma in a young adult: its similarities to clear cell sarcoma of the kidney.

We report an unusual case of renal sarcoma in a young adult. Histological examination demonstrated many similarities to the histopathological features of clear cell sarcoma of the kidney. Immunohistochemically, none of the intrinsic tumor cells showed positive staining with the antibodies against the intermediate filament proteins, epithelial membrane antigen, S100 protein, neuron-specific enolase, Leu-7 or myoglobin. The clinical course of this tumor was that of high grade malignancy, resulting in death with generalized metastases 13 months after tumor resection.

Immunohistochemical localization of vitamin B12 R-binder in salivary gland tumors. Implications for cell differentiation.

Vitamin B12 R-binder, a specific binding protein for vitamin B12, was studied immunohistochemically in normal and 106 neoplastic salivary gland tissues with a monoclonal antibody against vitamin B12 R-binder (R-binder). In normal salivary glands, R-binder localization was restricted to the ductal systems and to mucous acinar cells; serous acinar cells, myoepithelial cells and stromal connective tissues were consistently negative. Among salivary gland tumors, R-binder was present in 87% of pleomorphic adenomas, 100% of monomorphic adenomas, and 40% of adenoid cystic carcinomas; positivity was observed only on luminal surfaces of small ductular elements, indicating that the components closely related to ductal differentiation were rather small in population. R-binder could be detected both in lacunar and non-lacunar cells within chondroid areas of pleomorphic adenomas, suggesting the possibility that chondroid regions arise from metaplastic changes in ductal epithelial cells. In mucoepidermoid tumors, mucous cells and focal squamous cells exhibited cytoplasmic staining. The staining pattern for R-binder in epithelial components of adenolymphomas showed close similarities to those found in normal large excretory ducts. Two acinic cell tumors and one case each of myoepithelioma and malignant myoepithelioma exhibited negative reactivity for R-binder, showing that these neoplasms are solely composed of tumor cells without the characteristics of ductular differentiation. The immunohistochemical examination of salivary gland tumors, employing a monoclonal anti-R-binder antibody, may have some implications for cellular heterogeneity and differentiation in various tumors.

Distribution of vitamin B12 R-binder in carcinomas of the digestive tract.

To evaluate whether the increase in serum transcobalamin I, seen in patients with carcinoma, is caused by synthesis of R-binder to tumour cells, the distribution of vitamin B12 R-binder in 125 malignant growths of the digestive tract was studied. Positive staining for R-binder with immunoperoxidase was observed in 85 (70%) carcinomas. Positive staining for R-binder was observed in all four cholangiocarcinomas studied, but was absent in nine hepatocellular carcinomas. These findings suggest that determination of R-binder in liver tumours may be of some value in differentiating hepatocellular carcinomas and cholangiocarcinoma, and that synthesis of R-binder by tumour cells causes an increase in serum transcobalamin I.