Monoclonal antibody DS6 detects a tumor-associated sialoglycotope expressed on human serous ovarian carcinomas.

A newly developed murine monoclonal antibody, DS6, immunohistochemically reacts with an antigen, CA6, that is expressed by human serous ovarian carcinomas but not by normal ovarian surface epithelium or mesothelium. CA6 has a limited distribution in normal adult tissues and is most characteristically detected in fallopian tube epithelium, inner urothelium and type 2 pneumocytes. Pre-treatment of tissue sections with either periodic acid or neuraminidase from Vibrio cholerae abolishes immunoreactivity with DS6, indicating that CA6 is a neuraminidase-sensitive and periodic acid-sensitive sialic acid glycoconjugate ("sialoglycotope"). SDS-PAGE of OVCAR5 cell lysates has revealed that the CA6 epitope is expressed on an 80 kDa non-disulfide-linked glycoprotein containing N-linked oligosaccharides. Two-dimensional non-equilibrium pH gradient gel electrophoresis indicates an isoelectric point of approximately 6.2 to 6.5. Comparison of the immunohistochemical distribution of CA6 in human serous ovarian adenocarcinomas has revealed similarities to that of CA125; however, distinct differences and some complementarity of antigen expression were revealed by double-label, 2-color immunohistochemical studies. The DS6-detected CA6 antigen appears to be distinct from other well-characterized tumor-associated antigens, including MUC1, CA125 and the histo-blood group-related antigens sLea, sLex and sTn.

Immunohistochemically detecting target antigens in patient biopsies for tailoring monoclonal antibody based cancer therapy.

Immunohistochemical analysis of biopsies, cytology specimens or surgical resection specimens using antibodies directed towards tumor-associated antigens, lineage or differentiation antigens is a technique often used by surgical pathologists to aid in establishing the correct histologic classification of malignant tumors. With the proliferation of experimental approaches to cancer treatment using monoclonal antibodies as targeting agents, it is anticipated that surgical pathologists will increasingly be receiving requests from clinicians to define the antigen profile in biopsy specimens, even when not necessary to render the correct tumor classification. Clinicians may use the immunohistochemically delineated antigen profiles provided by surgical pathologists to plan tailored treatment regimens utilizing monoclonal antibodies to the antigens expressed in the tumor biopsy to target anticancer therapeutic agents. Some of the potential problems in such a process might include the differing sensitivities, and perhaps specificities, of the antibodies used for analyzing the surgical pathology biopsy specimens compared to the monoclonal antibodies actually used in vivo. Our approach to this dilemma is to develop murine monoclonal antibodies to tumor-associated antigens that can reliably be used to detect antigens in routinely processed surgical pathology specimens as a starting point for further therapeutic monoclonal antibody development.

Embolectomy of a Bird's Nest Vena Caval Filter.

In this case report we describe a successful embolectomy of a partially migrated Bird's Nest Caval Filter with attached embolic material. We used transesophageal echocardiography to guide the surgical approach. The patient recovered uneventfully from both the embolectomy and the subsequent pelvic operation.