Different Behaviors in the Production and Release of SCC Antigen in Squamous-Cell Carcinoma

Abstract

Squamous-cell carcinoma antigen (SCC antigen), formerly referred to as TA-4, is closely related to the grade of differentiation. Immunohistochemical studies have demonstrated that SCC antigen is also increased in the keratinizing or large-cell nonkeratinizing type of squamous-cell carcinoma but not in the small cell type. On the other hand, the appearance rate of SCC antigen in the blood circulation is almost the same in these three types of squamous-cell carcinoma. The present study was conducted to clarify the discrepancy in the production and release of this tumor marker using a squamous-cell carcinoma cell line, SKG-IIIa. SKG-IIIa cells were treated with 10 μM 5-azacytidine, a potent hypomethylating agent, to obtain several sublines with different behavior in the production of SCC antigen, and cloned by a limiting dilution technique. One subline (B-5) released significantly greater amounts of SCC antigen into the incubation medium as compared with other sublines (A-5). In in vivo studies, groups of nude mice received subcutaneous injections of the A-5 or B-5 subline, and the serum SCC antigen levels were determined after the animals exhibited palpable tumors. The serum levels of SCC antigen were significantly higher in the animals inoculated with the B-5 cells than in those inoculated with the A-5 cells. On the other hand, fiow-cytometric analysis and immunohistochemical studies using a polyclonal antibody revealed that the intracellular contents of SCC antigen were greater in the A-5 cells than in the B-5 cells. Radioautography was performed using a ¹²⁵I-labeled monoclonal antibody specific against the acidic fraction of this marker, a dominant form released outside the cells, which revealed that the production of the acidic fraction was somewhat greater in the B-5 cells than in the A-5 cells. These results suggest that the production and release of SCC antigen are different phenomena in squamous-cell carcinoma and that the release of SCC antigen is likely influenced by the production of the acidic fraction.

Expression of mRNA of SCC Antigen in Squamous Cells

“…B-5, showed apparently weaker immunostaining of SCC antigen but a greater release of SCC antigen than another subclone. A-5 cells [8], In our preliminary data. B-5 cells showed a greater expression of mRNA than A-5 cells (data arc not shown).…”

Malignant Brenner Tumors of the Ovary and Tumor Markers: Case Reports

“…Monoclonal antibody cc49 against the CA72-4 antigen has demonstrated reactivity to the majority of human adenocarcinomas including colorectal, gastric, pancreatic, ovarian, endometrial, mammary and non-small-cell lung cancer with no or weak reactivity to normal adult tissues, with the exception of secretory endometrium (2). Monoclonal antibody mAb13 against the SCC antigen has demonstrated reactivity to squamous cell carcinoma (3). An immunohistochemical study demonstrated the presence of CA 125 and CA72-4 antigen intracytoplasm of undifferentiated epithelial cells in Case 1.…”

The Clinical Value of Squamous Cell Carcinoma Antigen in Cancer of the Uterine Cervix

“…At the periphery of the tumor growth the production of the acidic subtype is enhanced and also in serum samples from cervical cancer patients the SCC antigen consists mainly of the acidic subtype [14,15]. The monoclonal antibodies in serological immunoassays recognize all SCC antigen subtypes [16].…”