Studies on sialyltransferase isoenzymes in plasma of patients with breast cancer

CDw75 antigen expression in breast lesions

Alterations on the cell surface of the oligosaccharide portion of glycoproteins and glycolipids are thought to play a role in tumorigenesis. Sialyltransferase catalyzes the incorporation of sialic acid to the carbohydrate group of glycoconjugates. Sialyltransferase has been found elevated in different tumour tissues and in the serum of cancer patients. In the present study we have examined the expression of the beta-galactosyl alpha 2,6-sialyltransferase requiring epitope CDw75, with the monoclonal antibody HH2. 142 breast lesions were included. 21% of the carcinomas in situ and 35% of the invasive carcinomas showed a diffuse cytoplasmic staining. Seven cases of invasive carcinomas also showed a distinct membrane immunoreactivity. We found no correlation between reactivity for CDw75 in malignant lesions and their metastatic potential. Only five out of 11 primary tumours with metastases expressed CDw75 in the primary tumour. In the benign lesions, there was a positive reaction in proliferating lesions, e.g. intraductal papillomas (2 out of 3 cases) and in epithelial proliferations in fibrocystic disease (10 out of 14 cases). None of the four fibroadenomas and phyllodes tumours and only one out of 22 cases of normal breast tissues showed immunoreactivity for HH2. In the malignant lesions, CDw75 was more frequently expressed in the carcinomas of high malignancy grade. The high frequency of immunoreactivity among the benign breast lesions can be indicative of activation of the epithelial cells.

Sialyltransferase activity in plasma cells of multiple myeloma

A marked elevation of sialyltransferase activity (STA) was observed in a solid tumor of plasma cells, which had been removed from a patient with multiple myeloma (MM), as compared to normal lymphatic tissues. STA was also determined in mononuclear bone marrow cells of 10 patients with MM and found to be 12 times higher than that of bone marrow mononuclear cells from 5 patients with non-malignant disorders (with less than 1% plasma cells in the bone marrow aspirate). A significant correlation was found between STA and the number of plasma cells in the bone marrow aspirate.

Sialyltransferase activity and sialic acid levels in multiple myeloma and monoclonal gammopathy

A significant elevation of peripheral blood mononuclear cell sialyltransferase activity (STA) was observed in 14 patients with multiple myeloma (MM), and compared to 7 patients with monoclonal gammopathy of undetermined significance (MGUS) and to 10 controls. Serum sialyltransferase was significant higher in MM patients as compared to controls. It was also higher than in MGUS patients, but the difference here was not statistically significant. STA was also determined in mononuclear bone marrow cells of 5 patients with MM (with 50 to 100% plasma cells in the bone marrow aspirate) and found to be 19 times higher than that of bone marrow mononuclear cells from 6 patients with non-malignant disorders (with less than 1% plasma cells in the bone marrow aspirate). No significant differences were observed in peripheral blood mononuclear cell sialic acid levels between MM, MGUS and controls.

Malignant cell glycoproteins and glycolipids

The cell surface is involved in cell growth and division, cell-cell interaction, communication, differentiation and migration, and other processes likely to be involved in malignant transformation and/or the metastatic spread of cancer. Although there are many alterations of glycoproteins and glycolipids on the malignant cell surface, it is unclear whether these alterations are epiphenomena or an integral part of the malignancy process. This article reviews the recent literature and some earlier studies relevant for understanding emerging concepts and trends with respect to malignant cell glycoconjugates. Emphasis is on structural alterations of the carbohydrate portions of malignant cell glycoproteins and glycolipids and on the enzymes (glycosyltransferases and glycosidases) involved in their metabolism. Practical applications derived from malignant cell glycoconjugate studies are discussed briefly with respect to the diagnosis, staging, monitoring, and treatment of malignant disease. The review concludes by indicating which research areas on malignant cell glycoconjugates are likely to be fruitful in increasing our basic understanding of, and ability to deal effectively with, malignant disease.

The utilization of [3H] sugars by non-malignant and malignant human breast

The utilization of [3H] sugars and leucine by non-malignant and malignant human breast has been assessed using an organ culture technique with subsequent tissue autoradiography. The uptake of sugars by normal and hyperplastic breast was generally constant, with some differences observed in the utilization of galactose by acini of normal and hyperplastic tissues. After 24 h incubation localization was predominantly at the luminal cell periphery. The utilization of sugars by carcinomas was much more variable. Differences were observed between adjacent cells and cell groups of the same tumour. The uptake of individual sugars within a carcinoma was also varied being either similar to, or greater or lesser than normal breast. Variation between carcinomas was also present. No correlation between type and differentiation was noted in this respect, but there was between localization of sugars and differentiation. Better differentiated areas in tumours showed patterns similar to non-malignant breast whilst localization in poorly differentiated cell groups was cytoplasmic. The uptake of leucine was more constant and proved to be a useful indicator of viability. While this approach cannot give information with regard to differences in glycoprotein structure between non-malignant and malignant breast, it has been of value in determining the heterogeneity of tumour cells with regard to the enzymes involved in glycosylation. As such it would be of use in assessing the uniformity of response to agents modifying glycosylation.

Serum sialyltransferase and fucosyltransferase activities in patients with multiple myeloma

A significant elevation of serum sialyltransferase and fucosyltransferase mean activities was observed in 19 untreated patients with multiple myeloma. However, sialyltransferase mean activity was significantly lower in 13 other patients treated for 1-30 months with alkylating drugs and prednisolone. Such a definite decrease in serum enzyme activity on treatment was not recorded for fucosyltransferase. Instead, this activity was significantly increased in treated patients as compared to controls. The presenting clinical features of the 32 patients with multiple myeloma were the basis for a clinical staging system with regard to myeloma cell burden according to established criteria. In untreated patients (as opposed to treated ones), a significantly higher serum sialyltransferase (but not fucosyltransferase) activity was obtained among those 11 belonging to stage III than among the other eight with stages I and II, suggesting a link between tumour burden and enzyme activity. This assumption was further strengthened in those six patients followed lengthwise with regard to serum sialyltransferase activity. Concomitantly with objective evidence of change in tumour burden they showed corresponding alterations in sialyltransferase activity. The determination of sialyltransferase and fucosyltransferase activity in serum may be an additional contribution to refine initial assessment and follow-up of individual patients with multiple myeloma.

Detection of metastatic breast carcinoma cells by immunofluorescent demonstration of Thomsen-Friedenreich antigen

The Thomsen-Friedenreich antigen (TF-antigen), known as a precursor of the MN-blood-group system, has been suggested as a tumor-associated antigen of breast adenocarcinoma. In order to evaluate the TF-antigen as a tool in the histochemical detection of micrometastases, cryostat sections of 25 breast biopsies and 30 regionary lymph nodes were investigated. The study used a sensitive method for the fluorescent staining of the determining terminal disaccharide sequence of asialoglycophorin A by application of peanut agglutinin (PNA) and fluoresceinisothiocyanate-labeled F(ab')2 fragments of monospecific anti-PNA from rabbits. PNA binding was observed in 91% of the sections of predominantly ductal mammary carcinomas. In normal tissues and hyperplastic lesions, staining patterns were markedly different from that of malignant breast cells, and were confined to secretory glycoproteins. Lymph nodes, with histologically confirmed metastases of mammary carcinomas, showed specific PNA binding in the cytoplasm of tumor cells in 75% of cases. Even single malignant cells were demonstrable, which were not recognized at first by routine light microscopy. Fluorescent staining of lymph nodes, which were tumor-free in repeated histologic examinations, was confined to clearly diagnosible histiocytes in 3 of 15 cases. A sensitive indirect immunofluorescent technique demonstrating PNA binding is proposed to be of considerable value for the detection of single metastatic adenocarcinoma cells of the human breast.

Post-operative serum sialyltransferase levels and prognosis in breast cancer

Serum sialyltransferase (SST) activity was measured 10 days after mastectomy in 153 patients with operable breast cancer. Enzyme activity declined with time in storage (1-42 months). After correction for loss of activity in storage, patients with SST activity below the median value had a longer disease-free interval (DFI) than those with SST activity above the median, and this difference remained when patients were stratified by axillary nodal status, tumor size, and tumor grade. Survival was longer in patients with low SST activity. Post-operative elevation of SST indicates a poor prognosis in patients with operable breast cancer.

Serum sialyl transferase levels in patients with metastatic breast cancer treated by chemotherapy

Serum sialyl transferase (SST) was measured in 49 female patients with advanced breast cancer and 60 female controls. The mean SST level was significantly raised in patients with advanced breast cancer. There was no correlation between specific sites, or numbers of sites of metastatic disease and SST levels. The patients with advanced breast cancer were all treated with chemotherapy; in 13/21 responders there was a significant fall in SST and in 2 responders a significant rise in SST. The 6 patients who died after one course of chemotherapy had a significantly higher mean SST than those surviving longer. SST appears to lack sufficient specificity to be of practical value as a marker of response in patients with breast cancer treated by chemotherapy, though constant measurement of changes in SST may be of use in monitoring drug response. Raised SST at the commencement of chemotherapy may signify poor prognosis.