Tumor-associated antigens detected by autologous sera in urine of patients with solid neoplasms

Old and new serological biomarkers in melanoma: where we are in 2009

Biomarkers play an important role in the diagnosis and prognostic classification of various cancers and can be useful in monitoring the patient's clinical course of disease and response to therapy. Generally, biomarkers are proteins and their expressions are associated with malignant disease. In the majority of cases, the marker molecules are expressed by the tumour cells themselves or by the tumour microenvironment cells. Thus, most biomarkers can primarily be found in malignant tissues, but after active secretion or passive release at tumour destruction, they become detectable in body fluids such as blood. Besides morphological and histopathological biomarkers (anatomic site, type of the primary tumour, tumour size, invasion depth, vascular invasion and ulceration), an increasing variety of serological markers have been identified, providing the possibility of a more detailed diagnostic and prognostic subgrouping of tumour entities, up to and even changing existing classification systems. The goal of this review is to provide an overview of old and more recent serological biomarkers in malignant melanoma. We will first focus on confirmed and nonconfirmed serum tumour markers, followed by proteomic profiling, an innovative approach to identify new and better serological biomarkers in melanoma, and ending with the predictive factors for treatments in this pathology.

The history and future of melanoma staging

The evolution and progressive refinement of an internationally accepted melanoma staging system over the last 50 years has resulted in much greater accuracy and increased utility, but the staging process has become more complex and less intuitive. This raises the question of whether melanoma staging should continue to develop with ever-increasing levels of complexity, or whether attempts should be made to produce an alternative system that is simpler and more intuitive. The current, TNM-based American Joint Committee on Cancer (AJCC) staging system for melanoma incorporates only some of the prognostic factors of proven significance. However, the information that is now available about these and other, well-documented prognostic factors allows accurate prediction of an individual melanoma patient's prognosis using a computer-generated estimate. Thus an alternative staging strategy that could be considered in the future would be to use such an estimate to obtain a numerical score for each patient, based on all available information agreed to be of prognostic relevance. A stage grouping could then be assigned on the basis of that score, according to previously determined score ranges for each stage and substage. The advantages of such a system would be that it would allow more reliable comparison of treatment results within and between institutions, and would provide more equivalent stratification groups for patients entering clinical trials of new therapies and those entering adjuvant therapy trials. A further advantage would be that because there would be a direct link between staging and prognostic estimate, such a system would be more readily able to be understood in an intuitive fashion.

Endogenous immune response to early- and intermediate-stage melanoma is correlated with outcomes and is independent of locoregional relapse and standard prognostic factors

BACKGROUND

Standard prognostic factors, including precise staging of the regional lymph nodes, cannot accurately determine which early-stage melanomas will metastasize. The immune response to a 90-kd tumor-associated antigen correlates with occult nodal disease and survival of patients receiving vaccine therapy for melanoma. We hypothesized that this response might have prognostic significance independent of standard prognostic features.

STUDY DESIGN

Patients with primary melanomas 1.01 to 2.00 mm and tumor-negative regional lymph nodes were identified. Group 1 comprised 50 patients who died of metastases within 7 years after complete surgical treatment; group 2 comprised 50 patients who were matched with group 1 for six standard prognostic features but who lived at least 10 years without recurrence. Postoperative sera were analyzed for an immune complex to TA90 and for immunoglobulin-G and immunoglobulin-M antibodies against TA90.

RESULTS

Median thickness of the primary melanoma was 1.40 +/- 0.31 mm and 1.42 +/- 0.32 mm in groups 1 and 2, respectively; median Clark's level of invasion was III in both groups, and 26 patients in each group had ulcerated primaries. Median TA90-IC level and rate of TA90-IC positivity (optical density greater than 0.410) were 0.557 +/- 0.43 and 82%, respectively, in group 1 and 0.305 +/- 0.15 and 18%, respectively, in group 2 (p < 0.001). The anti-TA90 IgM level was significantly elevated in 12% of group 1 (median titer 1:150) and 62% of group 2 (median titer 1:800) (p < 0.001). There was no significant difference in anti-TA90 IgG levels between the two groups.

CONCLUSIONS

A positive TA90-IC level and absence of an anti-TA90 IgM response correlate with distant metastasis when melanoma is low risk or intermediate risk by standard prognostic factors.

Tumor-associated antigen TA90 immune complex assay predicts recurrence and survival after surgical treatment of stage I-III melanoma

PURPOSE

Immune complexes (IC) containing the tumor-associated antigen TA90 can be identified in the sera of melanoma patients. We have shown that an enzyme-linked immunosorbent assay for TA90-IC can detect subclinical metastasis before surgical treatment of early-stage melanoma. We assayed the TA90-IC levels of postoperative sera from patients with melanoma and evaluated their relationship to recurrence and survival.

PATIENTS AND METHODS

Multiple archival serum samples prospectively collected during postoperative surveillance of 166 patients with American Joint Committee on Cancer stage I, II, or III melanoma were analyzed for TA90-IC in a blinded fashion. Results were correlated with disease recurrence and survival determined by database and chart review.

RESULTS

TA90-IC status in the early postoperative period was strongly correlated with survival. Five-year overall survival rates were 84% for TA90-IC-negative patients and 36% for TA90-IC-positive patients (P =.0001). Respective 5-year disease-free survival rates were 74% and 24% (P =.0001). The TA90-IC assay was a significant predictor of survival for both stage II and III patients. Multivariate analysis identified TA90-IC status as the strongest independent prognostic factor for both overall and disease-free survival. The TA90-IC assay was elevated in 54 (77%) of 78 patients who developed recurrent disease, becoming positive 19 +/- 7 months before clinical evidence of recurrence. Overall, the assay detected recurrence with a sensitivity of 78% and specificity of 77%. Exclusion of patients receiving postoperative immunotherapy with a polyvalent melanoma cell vaccine increased sensitivity and specificity to 92% and 86%, respectively.

CONCLUSION

The TA90-IC assay can accurately predict survival and detect the presence of subclinical disease after surgery for melanoma, which should be useful in selecting patients for adjuvant therapy. Because the TA90-IC assay detected recurrence on an average of 19 months sooner than did routine clinical and radiographic evaluation, it may allow more timely therapeutic interventions.

Tumor-associated antigen TA-90 immune complex assay predicts subclinical metastasis and survival for patients with early stage melanoma

BACKGROUND

TA-90 is a tumor-associated antigen first identified in the urine and sera of patients with metastatic melanoma. In the early stages of disease, TA-90 is present in circulating immune complexes (ICs) that may be detected with an antigen specific enzyme-linked immunosorbent assay (ELISA). In this study, the authors evaluated the efficacy of the TA-90 IC assay in detecting subclinical metastasis of early stage melanoma and predicting the survival of patients with this disease.

METHODS

Archival sera were collected preoperatively from 114 patients who underwent wide excision with or without regional lymphadenectomy in the treatment of clinical Stage I melanoma. Sera were analyzed for TA-90 IC in a blinded fashion, and results were correlated with the patient's clinical course as determined by database and chart review. Subclinical metastases were considered present at the time of surgery if the lymphadenectomy specimen was pathologically positive and/or the patient subsequently developed recurrence.

RESULTS

The TA-90 IC assay predicted subclinical metastasis in 43 of 56 patients (P < 0.0001), with 14 false-positive and 13 false-negative results. Sensitivity and specificity for the detection of occult metastasis were 77% and 76%, respectively. Positive and negative predictive values were 75% and 77%, respectively. Fifteen of 18 tumor positive regional lymph node basins (83%) and 34 of 46 recurrences (74%) were accurately predicted when considered independently (P < 0.004). Preoperative TA-90 IC status was also highly correlated with survival: 5-year overall and disease free survival rates were 63% and 46%, respectively, for the TA-90 IC positive group, compared with 88% and 82%, respectively, for the TA-90 IC negative group (P=0.0001). A multivariate analysis with standard prognostic variables identified preoperative TA-90 IC status as a strong, independent prognostic factor for both overall and disease free survival.

CONCLUSIONS

To the authors' knowledge, TA-90 is the first tumor marker that accurately predicts subclinical metastatic disease and survival for patients with early stage melanoma. For this reason, the TA-90 IC assay has the potential to improve dramatically the prognostic evaluation of patients with this disease. Its role in postoperative risk stratification and early detection of recurrence is being evaluated in a prospective study.

Urotherapy for patients with cancer

Cancer cells release various antigens, some of which appear in the urine. Oral autourotherapy is suggested as a new treatment modality for cancer patients. It will provide the intestinal lymphatic system with the many tumor antigens against which antibodies may be produced. These antibodies may be pierced through the blood stream and attack the tumor and its cells.

Monoclonal antibody-based ELISA to detect glycoprotein tumor-associated-antigen-specific immune complexes in cancer patients

This report describes the development and applicability of a tumor-associated-antigen-specific immune complex (IC) detection assay to denote the presence of tumor cells in a cancer host. This assay utilizes a murine monoclonal antibody, AD1-40F4, which was produced to a glycoprotein tumor-associated antigen (TAA). In Western blot, the murine monoclonal antibody recognized a 90-100 kD subunit of the antigen. This antigen is immunogenic in cancer patients and induces formation of endogenous antigen-antibody complexes. Analysis of 250 sera from normal individuals and 419 sera from cancer patients revealed that a significantly (P less than .0005) greater proportion (234/419; 55.9%) of cancer sera was positive for the marker than the normal sera (8/250; 3.2%). The incidence of the 90 kD-TAA-specific-IC was consistently and significantly higher in melanoma (58.5%; 38/65), sarcoma (52.9%; 83/157), and carcinoma of breast (50.9%; 58/114), lung (68.2%; 30/44), and colon (64.1%, 25/39) than in the normal group. The age of serum donors did not affect the incidence of the reactivity. Also, at least in the cancer group the gender of the serum donor did not affect the incidence of the 90 kD-TAA-specific-IC positivity. In a retrospective study where sequential serum samples obtained postoperatively from 105 patients with melanoma were analyzed, the 90 kD-TAA-specific-IC could be detected in 72 (69%) of patients several years before the appearance of clinically detectable disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Complement-dependent lysis of tumor cells by a baboon IgM antibody to a tumor-associated antigen

We developed a high-titer polyclonal antiserum to a glycoprotein tumor-associated antigen (TAA) by immunization of a baboon with the purified glycoprotein antigen. The baboon serum was fractionated into IgG and IgM components by DEAE Affi-Gel blue chromatography. The ability of the baboon IgM anti-TAA antibody to effect tumor cell lysis in the presence of complement was tested using a chromium-release assay. The baboon antibody was able to lyse melanoma target cells (20.8%-71.4% cytolysis), breast carcinoma cells (36.5%-38.9% cytolysis), and a neuroblastoma cell line (35.5% cytolysis) in the presence of complement but did not effect significant lysis of autologous lymphoblastoid cell lines (4.9% cytolysis) or peripheral blood lymphocytes from healthy volunteers (12.6% cytolysis). Cytolysis of melanoma target cells was completely inhibited by preabsorption of the IgM anti-TAA antibody with UCLA-SO-M14 (M14) cells and partially inhibited by preabsorption with several other melanoma cell lines. There was no significant inhibition of tumor cell lysis after preabsorption of the antibody with lymphoblastoid cell lines. Complement-dependent lysis of M14 targets could be blocked by addition of the purified antigen to the antibody prior to incubation with the tumor cells. Our results suggest that the glycoprotein TAA resides on the tumor cell surface and that the baboon IgM anti-TAA antibody recognizes the antigen on the cell surface and is able to fix complement and effect the lysis of the tumor cells.

Characterization of a 90-100 kDa tumor-associated antigen in the sera of melanoma patients

Using allogeneic antibody, we previously described a high-molecular-weight glycoprotein in the urine of 68% of melanoma patients. This glycoprotein has been termed urinary-tumor-associated antigen (U-TAA). A murine monoclonal antibody (MAb) specific for U-TAA (ADI-40F4) has been developed. By the use of ADI-40F4, U-TAA was detected in serum samples from 63% (33/52) of stage II and stage III melanoma patients, but from only 5% (1/20) of normal controls. This report describes the physical and immunochemical properties of U-TAA in the serum. The antigen elutes from a DEAE-Sephacel column in association with IgG in the void volume and as free antigen in a second peak. The molecular mass of the free antigen is 590-620 kDa and it sediments in the region of 28-29% sucrose by density gradient ultracentrifugation. Free antigen has an isoelectric point of 6.1. This high molecular weight antigen is composed of smaller subunits linked by reducible bonds. The ADI-40F4 reactive epitope resides on a 90-100 kDa subunit. These results provide evidence that U-TAA which is produced by melanoma cells in vitro is present in the circulation of melanoma patients.

Association between allo-immunoreactive and xeno-immunoreactive subunits of a glycoprotein tumor-associated antigen

Using allogeneic antibody, we previously described a tumor-associated antigen (TAA) in the urine of 68% of melanoma patients. The TAA was purified from urine of a melanoma patient and used as immunogen to develop a murine monoclonal antibody (AD1-40F4) and xenopolyclonal antibodies in a baboon. Sera from melanoma patients treated with whole melanoma cell vaccine were used as the source of human antibody to the glycoprotein antigen. Treatment with 2-mercaptoethanol and separation by sodium dodecyl sulfate/polyacrylamide gel electrophoresis resolved the high-molecular-mass glycoprotein TAA into smaller subunits. Immunoblot analysis indicates that the murine monoclonal antibody (AD1-40F4) recognized a 90-100-kDa subunit of the antigen while human anti-TAA antibodies primarily recognized a 65-kDa subunit in addition to the 90-100-kDa subunit. Baboon polyclonal antibodies recognized the same subunits plus a 120-kDa subunit. Blocking studies indicated that the murine monoclonal and baboon polyclonal antibodies recognized the closely related epitopes on the 90-100-kDa subunit, while human antibodies recognized an epitope entirely distinct from that recognized by the mouse antibody. These results demonstrate the epitope complexity associated with the high-molecular-mass glycoprotein TAA.

Detection of a tumor-associated glycoprotein antigen in serum and urine of melanoma patients by murine monoclonal antibody (AD1-40F4) in enzyme immunoassay

The urine of 68% of melanoma patients contains a high molecular weight glycoprotein which is expressed by melanoma cells and reacts with autologous antibody. Since high levels of this antigen in urine correlate with disease recurrence in surgically treated melanoma patients, it has been termed urinary tumor-associated antigen (U-TAA). We report the development of a murine monoclonal IgM antibody (AD1-40F4), which is specific for U-TAA. AD1-40F4 showed the same pattern of reactivity as the allo-antibodies previously used for the detection of U-TAA. The antigen recognized by AD1-40F4 has a high molecular weight (590-620 kilodaltons [kd]) and is heat stable. The AD1-40F4-reactive epitope is a protein. When AD1-40F4 was applied in an enzyme immunoassay, it allowed for the detection of U-TAA in the serum of 64% (33/52) of melanoma patients as opposed to only 5% (1/20) of normal controls. Thus, the murine monoclonal antibody AD1-40F4, which has been specifically developed against an allogeneic antibody defined antigen, U-TAA, appears to be important for immuno-prognosis of human melanoma.

A prospective postoperative evaluation of urinary tumor-associated antigens in sarcoma patients. Correlation with disease recurrence

Tumor-associated antigens (TAA) excreted into the urine of sarcoma patients can be detected by the complement-fixation assay. The authors prospectively measured TAA levels in the urine of 50 sarcoma patients postoperatively to determine whether reappearance of antigen in the urine would be predictive of disease recurrence. Twenty-five patients developed recurrence of their disease in the postoperative period, and 24 (96%) had reappearance of antigen in the urine 10.1 +/- 9.2 months prior to clinical evidence of recurrence. Of the 25 patients who remained disease free (mean follow-up, 48 months), 23 of 25 (92%) were urinary-antigen negative at last follow-up, although 8 patients had transient elevations of urinary TAA early in the postoperative period. Results indicate that postoperative measurement of urinary TAA in sarcoma patients permits selection of a subset of individuals at high risk for the development of recurrence. This knowledge can be of assistance in the postoperative management of these patients.

Immune complexes in urine and serum of patients with bladder cancer

The urine and/or serum of 43 patients with bladder cancer was tested for the presence of immune complexes. Immune complexes were present more frequently in the urine (38 per cent) than in the serum (23 per cent). Urinary immune complexes were elevated in 10 per cent of the patients with no tumor (group 1), 25 per cent with superficial neoplasms (group 2) and 89 per cent with infiltrating or metastatic disease (group 3), which compared favorably to elevated serum immune complexes in 20, 25 and 33 per cent of the patients, respectively. The incidence of urinary immune complexes was statistically significant when compared in patients with and without active tumors (p less than 0.03), and when group 3 patients were compared to those in group 1 or 2 (p less than 0.01 and p less than 0.03, respectively). Unlike serum immune complexes urinary immune complexes appeared to correlate with the presence and stage of bladder cancer.

Excretion of tumor-associated antigen(s) in the urine of patients with colon carcinoma

Urine samples collected from patients with colon carcinoma and from normal donors were tested for antigenic activity by the microcomplement-fixation assay. When autologous serum was used as the antibody source, 65.4% (17/26) of the urine samples from patients with colon carcinoma were positive for antigen as opposed to only 10% (2/20) from normal volunteers. Absorption of a representative serum with cultured colon cancer cells completely removed reactivity against its autologous urine. Using this serum to screen urine from colon carcinoma patients, antigenic activity was found in 71.4% (30/46) of the samples; however, only 10% (2/20) of the urine samples from apparently healthy volunteers were positive. Analysis of urine samples collected from three patients before and after resection of their primary colon carcinoma and from nine patients undergoing hyperthermia for liver metastases revealed that two of the patients who had curative surgical procedures had marked decreases in urinary antigen levels by the second postoperative day, while the third patient whose disease was unresectable had no significant decrease. Seven of nine patients with metastatic disease had a greater than fourfold increase in antigen activity after hyperthermia and chemotherapy. These results suggest that tumor-associated antigens were excreted into urine, possibly the result of treatment-caused tumor necrosis. Therefore, assessment of tumor-associated antigen(s) in the urine of patients with colon carcinoma may serve as a marker for response to treatment of this disease.