Circulating tumour-associated mucin concentrations, determined by the CASA assay, in healthy women

Transient elevation of the tumor markers CA 15-3 and CASA as markers of interstitial lung disease rather than underlying malignancy in dermatomyositis sine myositis

A 37-year-old woman with severe interstitial lung disease associated with dermatomyositis sine myositis is reported. A thoracoscopic lung biopsy revealed organizing diffuse alveolar damage. Significantly elevated serum levels of the tumor markers CA 15-3 and CASA (cancer-associated serum antigen) were detected, but no evidence of an underlying malignancy (including breast and ovarian) was found on serial clinical and radiologic examinations. These levels gradually normalized as the interstitial lung disease responded to a combination of cyclophosphamide and corticosteroids. The use of the CA 15-3 and CASA assays to measure serum levels of the highly glycosylated, high-molecular-weight mucin MUC1 in interstitial lung disease has not been previously described. Clinicians should therefore be aware that elevation of these tumor markers may reflect the presence of interstitial lung disease rather than an underlying malignancy in patients with dermatomyositis, especially if the levels normalize after successful treatment of the lung disease.

Cancer-associated serum antigen level: a novel prognostic indicator for survival in patients with recurrent ovarian carcinoma

The aim was to examine the value of the pretherapeutic serum cancer-associated serum antigen (CASA) level as a prognostic factor for survival in patients with recurrent epithelial ovarian carcinoma. Serum levels of CASA and cancer antigen (CA)125 were prospectively determined in 70 consecutive patients with recurrent ovarian cancer before the start of second-line chemotherapy. Univariate and multivariate analyses of survival were performed. The median level of serum CASA was 6.5 U/mL (range: 0.2-1437 U/mL). Univariate analysis showed that patients with a CASA level >10.0 U/mL had significantly shorter survival than patients with CASA level < or =10.0 U/mL (P= 0.002). Using different CASA cutoff levels (6.0, 6.5, and 10.0 U/mL), multivariate Cox analyses identified CASA as an independent prognostic factor for survival at every cutoff level. The strongest prognostic function for CASA was found at a cutoff level of 10.0 U/mL (>10 vs < or =10 U/mL; hazard ratio, 2.7; 95% confidence interval, 1.6-4.7; P < 0.001). The pretreatment CA125 level was not found to be significantly associated with survival by any of the cutoffs (35, 65, 132, and 339 U/mL). A pretreatment elevated level of the tumor marker CASA is an adverse prognostic factor for survival in patients with ovarian cancer relapse.

Pre-existing T-cell immunity against mucin-1 in breast cancer patients and healthy volunteers

PURPOSE

There is evidence that some tumor patients are able to generate tumor-associated antigen (TAA)-specific T-cell immunity spontaneously. However, little is understood about the existence and nature of self-reactive T-cells that recognize TAA in healthy donors (HD).

METHODS

Human mucin (MUC-1), a highly glycosylated transmembrane protein, is a well characterized TAA expressed by epithelial tumors. We compared endogenous MUC-1-specific T-cell immunity of breast cancer patients (BCP) and healthy volunteers using two MUC-1-derived HLA-A*0201-restricted peptides (MUC-1(950-958), MUC-1(12-20)). Antigen-dependent interferon (IFN)-gamma and Granzyme B expression of T-cells were analysed by a reverse transcription-polymerase chain reaction (qRT-PCR)-based assay.

RESULTS

A 32% of BCP and 43% of healthy volunteers revealed pre-existent CD8+ T-cells specific for MUC-1(950-958) but not for MUC-1(12-20). In patients, MUC-1-specific T-cells have been detected mainly in early stage disease prior adjuvant therapy. Those T-cells showed MUC-1-dependent IFN-gamma production after short-term stimulation but no clear Granzyme B expression. However, after repetitive in vitro stimulations using peptide-pulsed CD40-stimulated B-cell lines as autologous antigen presenting cells (APC) T-cell lines exhibited lytic capacity against HLA-A*0201+/MUC-1+ tumor cells.

CONCLUSION

MUC-1(950-958) is a dominant tumor antigen against which CD8+ T-cells were found frequently in BCP as well as in HD. Until now, this was only known for MelanA/MART-1. In contrast to previous reports, MUC-1-specific immunity was not linked to gender or number of pregnancies in women. Whether MUC-1(950-958)-related immunity highlights a yet unknown cross-reactivity in HD remains unclear. The presence of MUC-1-specific T-cells in some BCP may reflect a balance between immune tolerance and immune defence during aetiopathology.

Conditions associated with antibodies against the tumor-associated antigen MUC1 and their relationship to risk for ovarian cancer

Many cancers, including ovarian, overexpress epithelial mucin (MUC1) and promote anti-MUC1 antibodies that may correlate with more favorable prognosis. By extension, risk for ovarian cancer might be reduced by preexisting MUC1-specific immunity. We measured anti-MUC1 antibodies in 705 control women, identified events predicting antibodies, and estimated ovarian cancer risk by comparing profiles of events generating antibodies in controls with those in 668 ovarian cancer cases. Factors predicting antibodies included oral contraceptive use, breast mastitis, bone fracture or osteoporosis, pelvic surgeries, nonuse of talc in genital hygiene, and to a lesser extent intrauterine device use and current smoking. There was a significant increase in the likelihood of having anti-MUC1 antibodies from 24.2% in women with 0 or 1 condition, to 51.4% in those with five or more conditions. By the same index of events, the risk for ovarian cancer was inversely associated with number of conditions predisposing to anti-MUC1 antibodies. Compared with having experienced 0 or 1 event, the adjusted risk for ovarian cancer decreased progressively with relative risks (and 95% confidence limits) of 0.69 (0.52-0.92), 0.64 (0.47-0.88), 0.49 (0.34-0.72), and 0.31 (0.16-0.61), respectively for women with two, three, four, and five or more events related to the presence of antibodies (P(trend) < 0.0001.) We conclude that several traditional and new risk factors for ovarian cancer may be explained by their ability to induce MUC1 immunity through exposure of MUC1 to immune recognition in the context of inflammatory or hormonal processes in various MUC1-positive tissues.

The epithelial mucin, MUC1, of milk, mammary gland and other tissues

MUC1 is a mucin-type glycoprotein that is integrally disposed in the apical plasma membrane of the lactating epithelial cell and protrudes from the cell surface into the alveolar lumen where milk is stored. Envelopment of milk fat globules by this membrane accomplishes their secretion and conveys MUC1 into milk. The human form of this mucin has been detected in many other organs, tissues and body fluids. It projects from the cell surface as long filaments. In the human and a number of other species, MUC1 is polymorphic due to variable numbers of a tandemly repeated segment 20 amino acids in length. The individual codominantly expresses two alleles for the mucin so that differences in its size among individuals and between the two forms of an individual are observed. The tandem repeats are rich in serines and threonines which serve as O-glycosylation sites. Carbohydrate content of MUC1, as isolated from milk of human, bovine and guinea pig, is approximately 50%. The oligosaccharides carry substantial sialic acid at their termini and this accounts for two putative functions of this mucin, i.e., to keep ducts and lumens open by creating a strong negative charge on the surface of epithelial cells which would repel opposite sides of a vessel, and to bind certain pathogenic microorganisms. MUC1 is protease resistant (trypsin, chymotrypsin and pepsin) and large fragments of it can be found in the feces of some but not all breast-fed infants. MUC1 has a highly varied structure because of its polymorphism, qualitative and quantitative variations in its glycosylation between tissues, individuals and species, and differences due to divergence in the nucleotide sequences among species. Sequencing of the MUC1 gene for various species is showing promise of revealing unique evolutionary relationships and has already indicated conserved aspects of the molecule that may be functionally important. Among these are positions of serine, threonine and proline in the tandem repeats and a high degree of homology in the transmembrane and cytoplasmic segments of the molecule.

Prostate-specific Antigen (PSA) and Cancer-Associated Serum Antigen (CASA) in Distinguishing Benign and Malignant Prostate Disease

The Prostate-Specific Antigen (PSA) and the Cancer-Associated Serum Antigen (CASA) assay for the MUC1 mucin were compared in the serum of 303 patients with malignant or benign prostatic disease. Using cutpoints of 4, 10, and 20 μg/l, PSA was elevated in 93%, 81%, and 64% of patients with prostate cancer (n = 113), with corresponding specificities of 55%, 84%, and 96% in benign prostate disease (prostatic hyperplasia or prostatitis, n = 190). Using the recommended cutpoint of 4 Units/ml, CASA was elevated in 38% of patients with prostate cancer, with a specificity of 91% in benign disease. PSA and CASA showed a poor correlation in prostate cancer (r = 0.367) and benign disease (r = 0.158), and CASA was elevated in some PSA negative samples. Used together, PSA ≥20 μg/l and CASA ≥4 kU/l gave perfect specificity in benign disease, with a corresponding sensitivity of 29% (positive and negative predictive values of 100% and 70%, respectively). However, this combination gave no improvement over the use of PSA alone, with sensitivity 47% when the cutpoint was raised to give perfect specificity. These data suggest that CASA is of little use as an adjunct to PSA in the differentiation of benign and malignant prostate disease.

CA15-3, CASA, MSA, and TPS as diagnostic serum markers in breast cancer

This is the first comparison of the three mucin based tests CA15-3, CASA, and MSA, and the cytokeratin-related TPS assay in breast cancer. The mucin markers were superior to TPS in receiver-operator analysis, though no marker was of use in the diagnosis of malignancy due to low sensitivity. Using cutpoints that gave 95% specificity in benign disease (n = 83), corresponding sensitivities in pre-treatment breast cancer (n = 123: 13 in situ, 54 stage I, 45 stage II, 4 stage III, 7 stage IV) were 17% (CA15-3), 16% (CASA), 13% (MSA), and 8% (TPS), with a strong relationship between marker levels and disease stage. These assays did not always detect the same patients, and the use of CA15-3 combined with CASA gave the highest sensitivity (23%), though this was not significantly better than the use of CA15-3 alone. Despite detecting similar antigens, these assays can show markedly different responses in some patients, indicating that one mucin-based test cannot be substituted for another.

Unusual contents of a dermoid cyst of the ovary removed by laparoscopy

Benign cystic teratoma (dermoid cyst) of the ovary is a common pathological entity. Usually, the cyst contains representative tissues of the 3 embryonic germ cell layers: ectoderm, mesoderm and endoderm. Sebaceous material, hairs, cartilages, teeth, even thyroid tissue are frequently observed. In this case, the tumour was a well-formed jaw and tongue, and was successfully removed via the laparoscope.

Serum mucin antigens CASA and MSA in tumors of the breast, ovary, lung, pancreas, bladder, colon, and prostate. A blind trial with 420 patients

BACKGROUND

The tumor markers CASA (cancer-associated serum antigen) and MSA (mammary serum antigen) have previously been shown to be useful in the clinical management of ovarian and breast carcinoma, respectively, but have not been assessed in other types of cancer. These assays were compared with carcinoembryonic antigen (CEA) and prostate-specific antigen (PSA) in a blind trial using sera from the Mayo Clinic-National Cancer Institute (NCI) Diagnostic Serum Bank.

METHODS

CASA and MSA were assessed retrospectively in a blind trial using 465 serum samples from the Mayo Clinic-NCI Diagnostic Serum Bank representing malignant and benign disease of the breast, ovary, lung, pancreas, bladder, colon, and prostate and age-matched and gender-matched healthy control donors. CASA, MSA, and PSA levels were determined using commercially available kits, and CEA values and clinical details were later provided by the Mayo Clinic.

RESULTS

CASA and MSA showed good reproducibility in 45 duplicate samples. CASA values were significantly elevated in the serum of patients with malignant tumors of the breast (44%), ovary (58%), lung (56%), prostate (48%), and bladder (54%), but not in those with benign conditions of these organs or pancreatic or colon cancer. MSA levels were only elevated significantly in cancers of the breast (52%) and ovary (58%). CASA showed significantly better sensitivity than either CEA (20%) or MSA (25%) in the detection of lung cancer, whereas CEA showed significantly superior detection of colon cancers (78%). CASA was not as sensitive as PSA in prostate cancer (48% versus 96%), but gave superior specificity in nonmalignant conditions of the prostate (93% versus 70%), although this was not statistically significant.

CONCLUSIONS

The commercial CASA and MSA assays are reliable and reproducible tests for these tumor markers. In addition to ovarian cancer, CASA is also elevated significantly in many patients with breast, lung, prostate, and bladder cancer and has potential clinical use in patients with these tumors. The use of the MSA assay appears restricted to breast cancer.