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Preclinical studies have demonstrated that recombinant IFN-alpha (rIFN-alpha) can enhance the tumor associated glycoprotein 72 (TAG-72) on tumors. To determine whether rIFN-alpha could enhance TAG-72 expression in vivo in patients, 15 women with breast cancer were randomized to receive daily injections of rIFN-alpha (3 x 10(6) units/m2 for 14 days) beginning on day 1 (group 1 = 7 patients) or on day 6 (group 2 = 8 patients). On day 3, all patients received a 10-20-mCi tracer dose of 131I-CC49, a high-affinity murine monoclonal antibody reactive against TAG-72, followed by a therapy dose of 60-75 mCi/m2 of 131I-CC49 on day 6. Whole body and single-photon emission computed tomography scans along with whole blood pharmacokinetics were performed following tracer and treatment phases. Hematological toxicity was considerable; reversible grade 3-4 neutropenia and thrombocytopenia was observed in 12 of 15 patients. Twelve of 14 patients tested developed human antimouse antibodies 3-6 weeks after treatment. For group 1 patients, whole blood residence time increased significantly between that predicted from the tracer doses and therapy doses (42.6 +/- 4.7 versus 51.5 +/- 4.8 h, respectively; P < 0.01). The calculated radiation absorbed dose to red marrow from therapy compared to tracer activity was also significantly higher for this group (1.25 +/- 0.35 versus 1. 07 +/- 0.26 cGy/mCi; P < 0.05). Treatment with rIFN-alpha was found to enhance TAG-72 expression in tumors from patients receiving rIFN-alpha (group 1) by 46 +/- 19% (P < 0.05) compared to only 1.3 +/- 0.95% in patients not initially receiving IFN (group 2). The uptake of CC49 in tumors was also significantly increased in rIFN-alpha-treated patients. One partial and two minor tumor responses were seen. In summary, rIFN-alpha treatment altered the pharmacokinetics and tumor uptake of 131I-CC49 in patients at the expense of increased toxicity.

Colorectal tissue biopsies were obtained from 110 patients diagnosed with primary colorectal carcinoma (tumor and normal colonic mucosa samples), 20 patients diagnosed with benign colorectal disease, and 31 healthy donors. The level of expression of tumor-associated glycoprotein 72 (TAG-72) was quantitatively measured in each sample using a double-determinant RIA with monoclonal antibodies B72.3 and CC49 and detecting the sialyl-Tn epitope; this assay was termed CA 72-4. Statistical analysis revealed a significant (approximately 10-fold) increase of TAG-72 expression in the colon tumor biopsies when compared with the expression in normal colonic mucosa from the same patients. A regression analysis revealed a significant correlation (r = 0.459; P < 0.001) between TAG-72 levels measured in biopsies from the tumor lesions and those found in the corresponding normal colonic mucosa. Furthermore, regression analysis showed a significant positive correlation between TAG-72 levels in the tumors and sera of the same patients (r = 0.491; P < 0.001). TAG-72 levels in normal colonic mucosa from healthy donors and patients diagnosed with colorectal cancer were compared. TAG-72 expression was 5-fold higher in the normal mucosa from the colorectal carcinoma patients. No relationship between TAG-72 tumor tissue content and stage of disease was found. Moreover, the correlation between TAG-72 distribution and degree of tumor differentiation observed (P < 0.05) was not any more evident when mucinous carcinomas were excluded. Finally, the results provide further evidence that TAG-72 may be considered an important early marker for colorectal cancer and/or other dysplastic colonic diseases. The statistical correlation between TAG-72 levels in tumors and circulating TAG-72 indicates that patients with elevated levels of serum TAG-72, as measured by the CA 72-4 assay, would be most suited for diagnostic and/or therapeutic intervention with the anti-TAG-72 monoclonal antibodies B72.3 or CC49 or vaccine trials using the sialyl-Tn epitope.

Immunohistochemical studies showed that TAG-72 is expressed in more than 80% of colorectal carcinomas, but is rarely expressed in normal epithelium and benign diseases. TAG-72 can also be found in the body fluids of patients with adenocarcinomas, and its direct measurement can be used in conjunction with immunocytochemical analysis to help in discriminating benign from malignant effusions. The evaluation of TAG-72 in serum of colorectal carcinoma patients showed a sensitivity of approximately 40%, comparable to that of the widely used CEA. TAG-72 serum levels correlate with the stage of disease, suggesting its utility in discriminating between early-stage versus late-stage colon carcinoma. Longitudinal studies demonstrated that TAG-72 serum levels may be used as a predictive marker of recurrences. Moreover, the simultaneous measurement of TAG-72 and CEA serum markers improves the monitoring of recurrent disease. Therefore, these data suggest that TAG-72 is a well suitable marker for colorectal cancer.

Purpose: The ability of interferons (IFNs) to enhance tumor-associated antigen expression may be an important approach to enhance the efficacy of some monoclonal antibody (MAb)-based protocols for tumor diagnosis and/or therapy. The present study was designed to determine whether systemic IFN alpha-2a administration (via the intramuscular [IM] route) could upregulate the expression of tumor-associated glycoprotein-72 (TAG-72) and/or carcinoembryonic antigen (CEA) at histologically confirmed sites of carcinoma., Patients and Methods: Eighteen patients diagnosed with gastrointestinal (GI) carcinoma received systemic IFN alpha-2a according to four dose schedules. In cohorts I and II, patients received two injections of 3 or 6 x 10(6) U IFN alpha-2a per injection, respectively. Patients in cohorts III and IV received the same doses of IFN alpha-2a, 3 and 6 x 10(6) U, respectively, but three injections were given. Tumor and normal colonic mucosa biopsies were obtained from each patient by endoscopy before IFN alpha-2a and after IFN alpha-2a at surgery. The levels of TAG-72 and CEA expression were measured by (1) immunohistochemistry and reported as percent antigen-positive tumor cells, as well as the relative staining intensity, and (2) a quantitative radioimmunoassay., Results: TAG-72 and CEA levels were consistently increased in tumor biopsies taken from patients in cohorts III and IV. For example, of 10 patients treated in cohorts III and IV, eight had enhanced TAG-72 expression when measured either as percentage TAG-72-positive tumor cells or as an increased MAb staining intensity following IFN alpha-2a. CEA expression in tumor biopsies from seven of 10 patients in cohorts III and IV was also elevated following IFN alpha-2a treatment. Quantitative analysis of TAG-72 and CEA levels in tumor biopsies confirmed higher tumor antigen levels following IFN alpha-2a administration. No such increases in TAG-72 or CEA levels were observed in tumor samples taken from patients in cohorts I and II. CEA or TAG-72 expression in samples of histologically confirmed normal colonic mucosa showed little or no change after IFN alpha-2a treatment., Conclusion: Systemic IFN alpha-2a administration can upregulate TAG-72 and CEA expression at distal tumor sites, which may play an important role in immunodiagnosis and therapy.

Among the new tumor markers that have been recently proposed, CA 72-4 is of particular interest, not only for its capabilities in diagnosing and monitoring certain neoplastic diseases, but also for its excellent specificity. Several studies focused on the potential clinical usefulness of CA 72-4 in gastrointestinal (GI) and gynecological cancer, showing a sensitivity of approximately 40% in colorectal and gastric cancer and 50% in ovarian cancer, with an overall specificity of more than 95%. Longitudinal evaluations of patients with either GI or gynecological malignant diseases demonstrated that significant elevations of CA 72-4 serum levels may be predictive of recurrent disease. Moreover, the combination of CA 72-4 with other known serum markers, such as CEA and CA 19-9 for GI cancer or CA 125 for ovarian cancer, indicated that an increase in the sensitivity can be achieved without substantial changes in the overall specificity, improving the possibility of monitoring these patients. In conclusion, these results provide a strong argument for the use of CA 72-4 in the management of these neoplastic diseases.

Objective: This study was performed to evaluate the clinical values of tumor-associated glycoprotein-72 serum levels alone or in combination with CA 125 in the diagnosis and monitoring of patients with ovarian cancer., Study Design: Serum samples from 293 patients, 142 with primary carcinoma and 151 with benign diseases of the genital tract, were evaluated for the presence of CA 125, tumor-associated glycoprotein-72, and carcinoembryonic antigen. All patients underwent surgery for the primary tumor, and stage was defined according to the classification of International Federation of Gynecology and Obstetrics., Results: When the measurement of serum tumor-associated glycoprotein-72 is combined with that of CA 125, the sensitivity for the detection of primary ovarian cancer increased from 60% to 73%, with no significant change in specificity, and resulted in a more accurate clinical assessment for detection of residual disease before the second-look procedure. In fact, when both markers were positive, 100% specificity was achieved; conversely, when both markers were negative, no residual disease was found., Conclusion: These findings suggest that tumor-associated glycoprotein-72 may be considered as a supplementary serum marker for CA 125, providing further clinical information for the diagnosis of primary and recurrent ovarian cancer.

Tumor-associated glycoprotein-72 has been recently suggested as a new serum marker for colorectal cancer. In fact, approximately 40 percent of colorectal cancer patients have positive tumor-associated glycoprotein-72 serum levels at the time of diagnosis, while only 3 percent of patients with benign diseases are positive. A longitudinal evaluation of colorectal cancer patients suggested the utility of combining the measurement of tumor-associated glycoprotein-72 with that of carcinoembryonic antigen to monitor disease status not only at the time of diagnosis, but also at the time of recurrence. Several reports have indicated that the expression of some tumor antigens in colorectal adenomas may correlate with those parameters conventionally considered as indicative of malignant transformation. The presence of tumor-associated glycoprotein-72 in colorectal adenomas has been recently correlated with preneoplastic lesions, suggesting that tumor-associated glycoprotein-72 may be considered as an early marker of neoplastic transformation. The evaluation of tumor antigens can be considered a new tool in the management of colorectal cancer.

Purpose: The study was designed to determine whether in vivo interferon gamma (IFN-gamma) administration could enhance tumor antigen expression on the surface of human tumor cells., Materials and Methods: Eight patients (six with ovarian and two with gastrointestinal tumors) with a diagnosis of adenocarcinoma with secondary malignant ascites were given weekly escalating doses of IFN-gamma (ie, 0.1 to 100 MU) intraperitoneally (IP) each week for 8 weeks. Tumor cells were isolated from the patients' ascites samples, which were collected three times per week: before and 24 and 48 hours post-IFN-gamma administration. The level of expression of tumor-associated glycoprotein-72 (TAG-72) and carcinoembryonic antigen (CEA) was measured using flow cytometry and immunocytochemistry., Results: IFN-gamma administered IP dramatically increased TAG-72 (as measured by binding of anti-TAG-72 monoclonal antibodies [MoAbs] B72.3 and CC 49) and CEA (measured by MoAb COL-1) expression on the surface of the carcinoma cells. The ascites-derived tumor cells from seven of the eight patients constitutively expressed TAG-72, and the level of TAG-72 expression was increased by IFN-gamma in all seven patients, as evidenced by the enhanced binding of anti-TAG-72 MoAbs to the tumor-cell surface. In some cases, IFN-gamma treatment increased the percentage of MoAb B72.3-reactive tumor cells from 10% to greater than 90%, and those changes were further corroborated by similar increases in the MoAb staining intensity observed with immunoperoxidase analysis. In addition, ascites-derived tumor cells from two patients with gastrointestinal carcinoma also expressed enhanced CEA levels after IFN-gamma. The increased TAG-72 and CEA expression were observed at low IFN-gamma doses (ie, 0.1 to 1.0 MU), which were well tolerated by all patients., Conclusions: The ability of IFN-gamma given IP to increase TAG-72 and CEA expression on tumor cells in vivo provides additional argument for the use of the cytokine as an adjuvant to enhance MoAb binding to human carcinoma-cell populations.

The presence of three distinct serum markers of carcinoma, tumor-associated glycoprotein 72 (TAG-72; as measured by the CA 72-4 assay), CA 19-9, and carcinoembryonic antigen (CEA), was evaluated in 194 patients diagnosed with either malignant (n = 94) or benign (n = 100) gastric disease. Of the 94 patients diagnosed with gastric carcinoma, the percentage of patients whose serum samples were positive for TAG-72, CA 19-9, or CEA was 42.6, 31.9, and 20.2%, respectively. Furthermore, fewer false positive samples were observed for TAG-72 than either CA 19-9 or CEA. The analysis of serum TAG-72, CA 19-9, and CEA levels in patients diagnosed with early (stage I and II) versus advanced (stage III and IV) disease revealed a significantly higher level of TAG-72 and CA 19-9 in the serum of patients with advanced stage gastric carcinoma. The serum samples were also analyzed to determine whether any advantage might be gained by simultaneously measuring two or more of the tumor markers. The data clearly indicate that the measurement of TAG-72 with CA 19-9 significantly increased the percentage of gastric carcinoma patients with positive serum levels of either antigen. This advantage was achieved with no significant increase in the number of false positives. Twenty-one patients were followed postsurgically for up to 3 years to determine whether the appearance or reappearance of TAG-72, CA 19-9, or CEA accurately predicted disease recurrence. Positive serum TAG-72 levels correlated with disease recurrence in 7 of 10 patients, compared with 5 and 2 patients for CA 19-9 and CEA, respectively. The findings suggest that serum TAG-72 as measured by the CA 72-4 assay may be a useful marker for late stage gastric carcinoma and its measurement alone or in combination with CA 19-9 may have utility in the clinical management of gastric carcinoma.

Eighty-two patients diagnosed with gastrointestinal (GI) adenocarcinoma were evaluated before and for 26 months after primary tumor resection for the presence of two serum tumor markers: tumor-associated glycoprotein-72 (TAG-72) and carcinoembryonic antigen (CEA). Elevated TAG-72 and CEA serum levels were found preoperatively in 32 (39%) and 34 (41.5%) of the 82 patients, respectively. The percentage of patients with elevated serum levels of either TAG-72 or CEA was 56.1% (46 of 82). Twelve (15%) patients who had normal CEA serum levels had elevated TAG-72 serum levels, and conversely, serum from 14 (17%) patients who were TAG-72 negative were CEA positive. Forty-five of the 82 patients were diagnosed with advanced disease (i.e., Stages C and D for colorectal, Stages III and IV for stomach), and 29 (64.4%) and 26 (57.8%) of those patients had elevated serum levels of TAG-72 or CEA, respectively. Elevated levels of either TAG-72 or CEA, however, were found in sera of 82.2% of patients with advanced GI cancer, which is an increase of 24.4% over the use of CEA antigen alone as a marker of disease. The measurement of both TAG-72 and CEA may improve the diagnosis of patients with GI malignant disease due to the apparent complementary association which exists between these tumor markers. Serum TAG-72 and CEA levels were monitored in 31 patients for varying lengths of time after resection of the carcinoma; 11 patients developed recurrent disease. Sera from nine of 11 (81.8%) of these patients had elevated TAG-72 levels and six of 11 (54.5%) had elevated CEA levels. Tumor marker elevations were observed either before (35 to 166 days) or at the time of diagnosis of recurrence. The elevation of one or both markers correlated with the clinical status in ten of 11 (90.9%) patients with recurrence. In addition, 20 patients who were clinically free of disease after more than 700 days' follow-up had normal serum levels of both TAG-72 and CEA. These findings suggest that the combined use of serum TAG-72 and CEA measurements may improve detection of recurrence in patients with GI cancer and may be useful in the postsurgical management of GI adenocarcinoma patients.

Sera were collected from 111 patients diagnosed with adenocarcinoma or nonadenocarcinoma malignancies who received different schedules of interferon (IFN)-gamma or IFN-beta ser alone or in combination. Serum carcinoembryonic antigen (CEA) and tumor-associated glycoprotein-72 (TAG-72) antigen levels were measured to determine whether interferon could enhance the tumor shedding and, thereby, the serum level of either tumor antigen. Less than 10% of the sera samples from patients diagnosed with nonadenocarcinoma malignancies (e.g., hairy cell leukemia, melanoma) had positive titers of TAG-72 or CEA, and interferon neither increased nor resulted in the appearance of either tumor antigen in those sera. In contrast, 59.2% and 75.4% of the patients with adenocarcinoma had positive serum levels of TAG-72 and CEA, respectively, prior to interferon. IFN-gamma and IFN-beta ser alone or in combination significantly increased serum TAG-72 or CEA in approximately 65% of those patients. The results suggest that interferon administration to patients with adenocarcinoma can result in increased serum levels of selected tumor-associated antigens used in the diagnosis of malignancy. These preliminary findings may be important in the development of new strategies to obtain more sensitive tumor antigen serum assays for the diagnosis and monitoring for disease progression of adenocarcinoma.

Tumor-associated glycoprotein-72 (TAG-72) is a high molecular weight glycoprotein found in the sera of patients diagnosed with gastrointestinal and other malignancies. TAG-72 was detected in the serum of a significant percentage of patients whose CEA levels were negative which underscores the possibility of exploiting the complementarity of the two tumor markers in the diagnosis of gastrointestinal (G.I.) carcinoma. Moreover, the measurement of TAG-72 may also be clinically useful in discriminating malignant from benign effusions. Serum TAG-72 and CEA levels were evaluated longitudinally in a series of patients following resection of primary G.I. carcinomas. A consistent relationship between efficacy of the surgery and serum TAG-72 clearance was observed, and TAG-72 alone or in combination with CEA accurately predicted recurrence of malignant disease in greater than 90% of the patients. The results indicate that TAG-72 is a new human serum tumor marker which, measured alone or in combination with other well established markers, may improve the diagnosis and/or clinical management of malignant disease.

A novel tumor marker, tumor-associated glycoprotein-72 (TAG-72), has been identified using monoclonal antibody (MAb) B72.3. Using immunohistochemical techniques, TAG-72 has been found in carcinomas of various origin including colon, stomach, breast, lung, prostate, and ovary, as well as in body fluids. The presence of TAG-72 in serum samples from 260 patients with colorectal disease (malignant or benign) has been evaluated using the CA72-4 assay. Approximately 40% of patients with colorectal cancer exhibit elevated levels of this marker; moreover, the presence of positive levels of TAG-72 significantly correlates with advanced stages of disease, suggesting that TAG-72 may be a good marker of advanced colorectal cancer. Only 2% of the patients diagnosed with colorectal disease had elevated TAG-72 serum levels indicating the high specificity of this marker. A comparative study with carcinoembryonic antigen (CEA) serum levels showed a complementarity of the two tumor markers; in fact, 49.6% of CEA negative cases scored positive for TAG-72. A longitudinal evaluation of TAG-72 serum levels in 31 patients with malignant disease was performed. The results indicate that patients with increasing TAG-72 serum levels postoperatively may be indicative of recurrent disease. In 60% of patients in which significant changes of CEA levels could not be detected, TAG-72 showed rising positive levels prior to clinical evidence of recurrent disease. These results suggest that the simultaneous use of TAG-72 and CEA serum markers may be useful in the diagnosis of recurrent disease and therefore play an important role in the clinical management of cancer patients.

Monoclonal antibodies (MAbs) which recognize a human tumor antigen, termed tumor-associated glycoprotein-72 (TAG-72), have successfully been used to localize primary as well as metastatic colorectal tumor lesions in patients. The localization of the anti-TAG-72 MAbs has also been exploited intraoperatively using a hand-held gamma probe. That procedure, termed radioimmunoguided surgery (RIGS), has identified occult tumors which were not detected using standard external imaging techniques. In another clinical trial, interferon-gamma (IFN-gamma) was administered intraperitoneally to patients diagnosed with either gastrointestinal or ovarian carcinoma with secondary ascites. Analysis of the tumor cells isolated from the malignant ascites revealed a substantial increase in TAG-72 expression on the surface of tumor cells isolated from seven of eight patients. The results provide evidence that the combination of an anti-carcinoma MAb with the administration of a cytokine, such as IFN-gamma, may be an effective approach for the detection and subsequent treatment, of colorectal carcinoma.

In vitro treatment with either type I or type II interferon (IFN) can selectively enhance the expression of several tumor antigens, such as the carcinoembryonic antigen (CEA) and the tumor-associated glycoprotein-72 (TAG-72) in different human carcinoma cell lines and result in enhanced level of monoclonal antibody (MAb) binding to the cell surface. In vivo animal studies demonstrated that treatment of athymic mice with a type I interferon [i.e. interferon-alpha (A)] significantly increased the expression of a 90 kDa tumor antigen which improved the targeting of a MAb to the carcinoma xenograft. More recent studies reported that in vitro IFN treatment of human adenocarcinoma cells isolated from human malignant serous effusions selectively increased the expression of TAG-72 and CEA. One can envision that the ability of these cytokines to upregulate the level of expression of human tumor antigens presents an important experimental model in which to study the regulation of markers often correlated with epithelial cell differentiation. In addition, the increase of selective MAb-defined antigens may also be exploited in an adjuvant setting to localize higher amounts of MAbs to the tumor cell surface and, thereby, improve the effectiveness of a MAb for tumor diagnosis and, possibly, therapy.

Monoclonal antibody (MAb) B72.3 was generated using a membrane-enriched fraction of a human mammary carcinoma biopsy. It has demonstrated reactivity to the majority of human adenocarcinomas including colorectal, gastric, pancreatic, ovarian, endometrial, mammary, and non-small cell lung cancer and no or weak reactivity to normal adult tissues, with the exception of secretory endometrium. The B72.3-reactive antigen, termed tumor-associated glycoprotein (TAG)-72, has been purified and used as an immunogen to generate B72.3 second generation MAbs. Since the source of purified TAG-72 was a human colon cancer (CC) xenograft, these MAbs have been given a CC designation. Twenty-eight CC MAbs, all immunoglobulin Gs, have been generated and shown to be reactive with TAG-72 and via both radioimmunoassay and immunohistochemical analyses show differential reactivity to carcinoma versus normal adult tissue biopsies. Nine CC MAbs (CC11, 15, 29, 30, 40, 46, 49, 83, and 92) were selected for further characterization. As a result of analyses using direct-binding radioimmunoassay to a range of human carcinomas, Western blotting, live cell surface binding assays, five liquid competition radioimmunoassays, and Ka measurements, all nine CC MAbs could be distinguished from each other and from B72.3. The Ka of B72.3 was determined to be 2.54 X 10(9) M-1; all the CC MAbs demonstrated higher KaS with MAbs CC92, 49, and 83 having KaS of 14.26, 16.18, and 27.72 X 10(9) M-1, respectively. These studies thus demonstrate that one or more of the anti-TAG-72 CC MAbs may be more efficient than B72.3, or useful in combination with B72.3, toward the further study of human carcinoma cell population and the diagnostic and therapeutic procedures presently utilizing MAb B72.3.