Lectin binding and steroid receptors in human breast carcinomas

Insights into animal and plant lectins with antimicrobial activities

Lectins are multivalent proteins with the ability to recognize and bind diverse carbohydrate structures. The glyco -binding and diverse molecular structures observed in these protein classes make them a large and heterogeneous group with a wide range of biological activities in microorganisms, animals and plants. Lectins from plants and animals are commonly used in direct defense against pathogens and in immune regulation. This review focuses on sources of animal and plant lectins, describing their functional classification and tridimensional structures, relating these properties with biotechnological purposes, including antimicrobial activities. In summary, this work focuses on structural-functional elucidation of diverse lectin groups, shedding some light on host-pathogen interactions; it also examines their emergence as biotechnological tools through gene manipulation and development of new drugs.

Steroid-coupled liposomes for targeted delivery to tumor

The steroidal receptors play a key role in protein synthesis and maintain the homeostasis in normal and diseased state, including tumorigenesis at the target tissues when overactivated. Thus steroidal receptors may act as potential targets for selective delivery of different therapeutic agents as they are overexpressed by a number of endocrinal tumors. The selective delivery of these agents may be a better treatment strategy for endocrinal cancer as it may also result in cytosolic and nuclear delivery of cytotoxic agents. In this review, the targeting potential of steroidal receptors for the drug or bioactive(s) delivery is discussed. The ligands that have been proven to be effective for specific steroidal receptors can be used as vectors for carrying the drug or drug-delivery system to the desired site of drug action in an optimum concentration. This strategy will not only minimize the undesired side effects associated with nonspecific delivery of drug, but will also maximize the drug utilization. Ligand-conjugated liposomes as a carrier of bioactives prevent passive diffusion of the encapsulated drug to normal cells, increase the time of circulation and reduce the undesirable side effects of a drug.

Mucin antigens expression and Ki-67 labeling in breast cancer: the peculiarity in scirrhous carcinoma

The expression of mucin-related antigens (Tn, T, Sialosyl-Tn [STn], DF3 [mammary-type apomucin related antigen], and intestinal-MRP [intestinal-type apomucin related antigen]) as well as Ki-67 labeling was examined in 58 mammary invasive ductal carcinomas (IDC) divided into 26 scirrhous subtype (SC) and 32 non-scirrhous subtype comprising papillotubular carcinoma and solid-tubular carcinoma (PT-ST). These data were analyzed in connection with the various pathological prognostic factors such as nodal status, tumor size, estrogen receptor status and histological grading of carcinomas. The results were as follows: (a) in SC, the expression rate of Tn was significantly higher in the cases with positive lymph node metastasis or with large tumor size (> 2 cm) than in those with negative lymph node metastasis or with small tumor size (< or = 2 cm); (b) in PT-ST, the expression rate of STn was higher in the cases with positive lymph node metastasis or with large tumor size than in those with negative lymph node metastasis or with small tumor size; (c) in SC, Ki-67 labeling was significantly higher in the cases with positive lymph node metastasis than in those with negative lymph node metastasis; and (d) in PT-ST, Ki-67 labeling was lower in the cases with positive lymph node metastasis than in those with negative lymph node metastasis. In conclusion, Tn antigen expression was correlated with pathological prognostic factors in SC but not in PT-ST, whereas STn antigen expression was correlated with pathological prognostic factors in PT-ST but not in SC.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of lectins in histopathology

Lectins are proteins and glycoproteins extracted predominantly from plants which have the capacity to bind sugars specifically. This property makes them of interest for histopathology since they will bind to saccharides forming parts of glycoproteins and glycolipids of tissue constituents. Lectins have and can be used as reagents for mucin histochemistry, to identify specific cells, in the recognition of glycoprotein alterations in disease states, in studies of infectious diseases, and in the assessment of glycoconjugate alterations occurring with malignancy. They can be used for both light microscopic and ultrastructural localisation and various methods are available. It is important though, to consider the nature of the glycoconjugates under study and select lectins appropriately because of their varying specificities and binding characteristics. A panel of lectins should be used to study a particular configuration. Care should be taken with tissue fixation and processing. It must be remembered that an open and critical mind should be kept concerning interpretation of results. At the present time lectins have a limited value diagnostically, but the binding of Ulex europeus agglutinin to endothelium is certainly of value.

Prognostic parameters in breast cancer

Carcinoma of the breast is the most common cancer in Australian women. Current methods of treatment and refinements in therapeutic regimens are based on our understanding of the biological behaviour of the disease. Several prognostic parameters have been identified which predict survival and allow the selection of patients who may benefit from adjuvant therapies. The more important of these parameters include tumour size, histologic type, histologic grade, axillary lymph node status, estrogen receptor status and tumour growth fraction. Diagnostic pathologists who are responsible for the evaluation of these parameters should be cognizant of their relative prognostic values and also of other factors such as cellular antigens, lectin binding and oncogenes which may have potential roles in predicting survival and therapeutic responses. This review provides an update of prognostic parameters which are assessed through examination of the excised specimen.

Lectin binding in the male breast

Twenty-four male breast lesions including ten normal, ten gynaecomastia, and four infiltrating carcinomas were studied for the presence and distribution of lectin binding carbohydrates. For comparison, tissue sections of five normal female breast lesions, ten each of fibrocystic disease, fibroadenoma, and carcinoma, were also included in this study. Formalin-fixed, paraffin-embedded tissues were tested with Glycine maximus (SBA), Dolichos biflorus (DBA), Triticum vulgaris (WGA), Concanavalia ensiformis (Con A), Lotus tetragonolobus (LTA), Arachis hypogaea (PNA), and Bandeiraea simplicifolia (BSAI). The lectin-binding patterns were similar in normal, gynaecomastia, and carcinoma, and were not pathognomonic to any male breast lesion. These lectin reactive patterns in the male breast appear to be similar to those reported for the female breast lesions.