Basic and clinical evaluation of an immunoradiometric competitive inhibition assay for 2----6 sialyl Lewis a antigen--2. Evaluation of clinical significance

The clinical significance of serum 2----6 sialyl Lewisa antigen was evaluated using "SLA 2----6 Otsuka" kits. Results indicated that the antigen was frequently elevated in sera obtained from patients with various cancers, including pancreas (73%), liver (67%), bilialy tract (66%), uterus (35%), and stomach (33%). Among other tumor markers examined, CA 19-9 (2----3 sialyl Lewisa) had a very similar cancer spectrum as 2----6 sialyl Lewisa. In the sera of patients with malignant disorders of digestive and respiratory organs, including stomach, intestine, pancreas, biliary tract and lung, the serum levels of CA19-9 tended to be higher than those of 2----6 sialyl Lewisa, usually exceeded those of CA19-9. This suggests that the 2----6 sialylation of Lewisa antigen is equally observed in malignant and non-malignant diseases, while the 2----3 sialylation is relatively specific to cancers. As a result, the ratio of the two antigens, CA 19-9: 2----6 sialyl Lewisa antigen ratio, exceeded 2.0 in most of the sera obtained from patients with malignancy, whereas the ratio was below 2.0 in most of patients with corresponding non-malignant diseases of those organs. The determination of the ratio may be clinically useful in the differential diagnosis of the malignant and non-malignant diseases in those organs.     

Basic and clinical evaluation of an immunoradiometric competitive inhibition assay for sialyl Tn antigen: (1). Evaluation of assay conditions and normal values. STN Study Group

An immunoradiometric competitive inhibition assay of the serum levels of the sialyl Tn antigen using "STN Otsuka" kits is described. The assay required only duplicate 50-microliters samples, and the concentration of sialyl Tn antigen in serum was determined by reference to a standard curve ranging from 0 to 400 arbitrary units/ml. The intra-and inter-assay reproducibilities were largely satisfactory. The serum levels of the antigen in normal individuals were not affected by ABO and Lewis blood type status of the tested individuals. Normal values were 25.5 +/- 9.8 in male, and 21.3 +/- 8.0 in female, and the difference was statistically significant at p less than 0.001. The serum level of the antigen was not affected by menstrual cycle or pregnancy in female, whereas the level of other tumor markers such as CA 125 was highly variable depending upon these conditions.     

Differences in prognosis of colorectal cancer patients based on the expression of sialyl Lewisa, sialyl Lewisx and sialyl Tn antigens in serum and tumor tissue

PURPOSE: To clarify the differences in prognosis of colorectal cancer patients based on the expression of sialyl Lewisaa sialyl Lewisx and sialyl Tn antigens in serum and tumor tissue. PATIENTS AND METHODS: Preoperative serum levels (by radioimmunoassay) and tumor tissue expression (by immunohistochemistry) of these antigens were simultaneously determined in 52 patients. For each antigen, patients were classified into one of four groups: Group S-/T-, S-/T+, S+/T- and S+/T+. (S denotes serum, T denotes tumor tissue, and negative and positive represent expression). RESULTS: For sialyl Lewisa antigen, the survival time of Group S+/T+ was significantly shorter than Group S-/T- or Group S-/T+ (p=0.027 or p=0.032, respectively). For sialyl Lewisx antigen, the survival time of Group S-/T+ was significantly shorter than Group S-/T- (p=0.048). CONCLUSION: Increased expressions of sialyl Lewisa antigen in serum and sialyl Lewisx antigen in tumor tissue may be associated with poor prognosis in colorectal cancer patients.     

Preoperative serum levels of sialyl Lewis(a), sialyl Lewis(x), and sialyl Tn antigens as prognostic markers after curative resection for colorectal cancer.

In this study, we examined the preoperative serum levels of sialyl Lewisa, sialyl LewisX, sialyl Tn, and carcinoembryonic antigen in 243 colorectal cancer patients in order to clarify the role of these antigens as prognostic factors after curative surgery. The patients were divided into two groups: low and high antigen groups (lower and higher than a selected diagnostic-based cut-off value). Patients with high serum levels of sialyl Lewisa and carcinoembryonic antigen had shorter disease-free intervals than those with low serum levels of the respective antigen, although sialyl Lewisx and sialyl Tn showed no significant differences. Multivariate analysis revealed that three independent prognostic variables, including depth of tumor invasion, lymph node metastasis, and serum sialyl Lewisa level, did prove to have value in predicting disease-free interval. In conclusion, among the four antigens examined in this study, the preoperative serum level of sialyl Lewisa is the only independent prognostic variable for recurrence after curative resection of colorectal cancer.     

Diagnosis and follow-up of ovarian cancer by a combination assay of serum sialyl SSEA-1 antigen and CA125 levels

We used a combination assay of serum sialyl SSEA-1 antigen (SLX) and CA125 levels, and evaluated the clinical usefulness of this technique for a diagnosis of ovarian cancer and follow-up of the patient with ovarian cancer. In 28 patients with ovarian tumors, the sera of 8 (66.7%) of 12 with ovarian cancer and 5 (71.4%) of the 7 with endometriosis (endometrial cyst) were positive for both SLX and CA125, but serum SLX level was 50 U/ml or less in all these 5 SLX-and-CA125 positive patients with endometriosis. The sera of all 9 patients with benign ovarian tumor were negative for both tumor markers. No patient with endometriosis was negative for both markers. The diagnostic accuracy (true positive rate X true negative rate) of the combination assay for ovarian cancer was 50.3% when the cut-off value of the serum SLX was 38 U/ml but improved to 81.8% when the value was set at 50 U/ml. From the above observations, a combination assay of serum SLX and CA125 is promising method for the differential diagnosis of malignant and benign ovarian tumors. Our results also suggest that to improve the diagnostic accuracy, the cut-off value of the serum SLX level should be 50 U/ml for ovarian tumors alone. We found following-up two cases of ovarian cancer that the serum SLX level is not affected by the ascites and inflammation. We expect that this combination assay of serum SLX and serum CA125 will be beneficial for diagnosis and follow-up of ovarian cancer.     

Basic evaluation of an immunoradiometric competitive inhibition assay for sialosyl-Tn antigen in sera in women. Assay conditions and normal values.

The assay conditions needed for an immunoradiometric competitive inhibition assay of sera in healthy women were studied using the monoclonal antibody TKH2, which is known to recognize specifically sialosyl-alpha 2,6-GalNAc alpha 1-0-serine/threonine (S-Tn) antigen, a mucinous cancer-related antigen. Stable results were obtained with an incubation time of 1.5 hours at room temperature. The intra-assay and inter-assay coefficients of variation were 3.27% and 3.07%, respectively. The mean (+/- standard deviation [SD]) levels of serum S-Tn in 602 healthy women was 21.2 U/ml (+/- 8.4 U/ml). Values showed a normal logarithmic distribution. Although slightly higher levels were seen in postmenopausal compared with premenopausal women, the differences were not significant. The cutoff value of 41 U/ml was determined from data obtained in 602 healthy women; higher levels were observed in only 2%. Serum S-Tn levels were not strongly influenced by Lewis or ABO (H) blood type, smoking, pregnancy, parturition, or phase of menstrual cycle. The use of the S-Tn antigen as a tumor marker for various gynecologic cancers requires study.     

Circulating serum STN antigen as a prognostic marker in epithelial ovarian cancer]

Circulating serum sialyl Tn (STN) antigen levels were measured in 89 patients with epithelial ovarian cancer. Survival at 5 years for patients with STN-negative (serum STN levels less than 50 U/ml) versus STN-positive tumors (serum STN levels greater than or equal to 50 U/ml) was 76.9% versus 10.8%, respectively (p less than 0.05). The overall survival probability was worse in patients with STN-positive sera. Percent progression-free survival at 5 years for patients with STN-negative versus STN-positive tumors was 51.9% versus 5.4%, respectively (p less than 0.05). The overall progression-free survival was shorter in patients with STN-positive sera. Multivariate regression analysis revealed that positive STN antigen level in sera is an independent predictor of poor prognosis in epithelial ovarian cancer.     

A radioimmunometric assay for circulating tumor-associated glycoprotein (TAG-72) using the antigen determinant CA 72-4

Tumor-associated glycoprotein (TAG-72) is an antigen recognized by monoclonal antibody (MAb) B 72.3 which was generated against a membrane enriched fraction of human mammary carcinoma cells. CA 72-4 is a novel antigen determinant on TAG-72 and is a quantitative radioimmunometric assay system utilizing two MAbs (CC-49, B 72.3) which react with circulating TAG-72 expressed by human carcinomas. We have employed the CA 72-4 RIA system to measure the antigen in sera. The optimum condition for this assay was found to be a 4 hour incubation at 37 degrees C for the first reaction and a 20 hour incubation at 4 degrees C for the second reaction. Under these conditions, intra-assay variation of the control sera was C.V. 3.0-5.2% and inter-assay variation was 5.6-8.3%. The mean +2 SD of CA 72-4 concentration in 468 healthy persons was 3.9 U/ml. Therefore, less than 4.0 U/ml was taken as the cut off level for the CA 72-4 serum assay. The largest population in healthy persons was at the range of 1.5-2.0 U/ml. Only 15 of 468 persons (3.2%) demonstrated serum CA 72-4 levels more than 4.0 U/ml. These data thus indicate the efficacy of CA 72-4 RIA system for the serum assay as a novel tumor marker. The clinical evaluation of CA 72-4 in patients with epithelial malignancies is now underway.     

Basic and clinical evaluation of an immunoradiometric competitive inhibition assay for sialyl TN antigen: (2). Evaluation of clinical significance. STN Study Group

The clinical significance of serum sialyl Tn antigen as a tumor marker was evaluated using "STN Otsuka" kits. Results indicated that the antigen was frequently elevated in sera from patients with ovarian cancers (43.1%, 140/325), including serous cystadenocarcinoma (51.6%, 63/122), mucinous cystadenocarcinoma (55.6%, 30/54), endometrioid carcinoma (56.5%, 13/23), and mesonephroid carcinoma (40.0%, 6/15). The positive frequency of sialyl Tn antigen in patients with ovarian carcinoma was less than the frequency of CA 125 (75.5%, 194/257) or sialyl SSEA-1 (47.2% 83/176). However, the false positive rate of sialyl Tn antigen in patients with benign gynecological disorders (3.7%, 15/401) was much lower than the false positive rates of other antigens; such as CA 125 (48.4%, 155/320) and sialyl SSEA-1 (19.2%, 51/266). The serum level of sialyl Tn antigen reflected the clinical activity of the disease quite well in patients with ovarian cancers. The sialyl Tn antigen was concluded to be a useful serum tumor marker for ovarian cancers.     

Serum sialyl Tn as an independent predictor of poor prognosis in patients with epithelial ovarian cancer.

PURPOSE: Monoclonal antibody (moAB) TKH-2 directed to the tumor-associated O-linked sialyl 2-6-alpha-N-acetylgalactosaminyl (sialyl Tn; STN) epitope was generated by immunization with ovine submaxillary mucin (Kjeldsen et al, Cancer Res 48:2214-2220, 1988). We investigated whether circulating serum levels of STN antigen might influence the prognosis of patients with ovarian cancer. PATIENTS AND METHODS: Serum samples were obtained from 126 healthy nonpregnant women, 157 patients with benign gynecologic disease, and 89 patients with histologically proven epithelial ovarian cancer. Circulating serum STN-antigen concentrations (U/mL) were determined by a competitive radioimmunoassay kit (Otsuka Assay Laboratories, Tokushima, Japan) in a one-step procedure. RESULTS: Serum antigen levels were elevated in 48.3% of the patients. The levels of STN antigen were significantly higher in the sera of patients with cancer when compared with levels in benign and healthy controls (P less than .05). The 5-year survival rate for patients with STN-negative (serum STN levels less than 50.0 U/mL) versus STN-positive (greater than or equal to 50 U/mL) tumors was 76.9% versus 10.8%, respectively (P less than .05). The progression-free interval (PFI) at 5 years was 51.9% versus 5.4%, respectively (P less than .05). The overall survival probability and PFI were worse in patients with STN-positive sera. Multivariate regression analysis revealed that stage, residual tumor size, positive STN, performance status, and histologic grade were the five important variables for predicting overall survival. CONCLUSION: We conclude that a positive STN-antigen level in sera is an independent predictor of poor prognosis in ovarian cancer.     

Quantitative and qualitative characterization of human cancer-associated serum glycoprotein antigens expressing epitopes consisting of sialyl or sialyl-fucosyl type 1 chain

The levels of carbohydrate antigens having epitopes consisting of type 1 chain (R----Gal beta 1----GlcNAc beta 1----3Gal beta 1----R) in the sera of patients with various malignant and nonmalignant disorders have been investigated with the use of three monoclonal antibodies, N-19-9, FH-7, and FH-9. Serum levels of 2----3 sialylated Lea antigen and 2----6 sialylated Lea antigen, defined respectively by antibodies N-19-9 and FH-7, were found to be frequently high in patients with cancer of the digestive system, particularly pancreatic cancer. High levels of 2----3,2----6 disialylated Lc4 antigen, defined by antibody FH-9, were less frequent in cancer patients when compared with the other two antigens. In patients with nonmalignant disorders, especially renal and autoimmune diseases, serum levels of the two type 1 chain antigens defined by FH-7 and FH-9 were more frequently high than that defined by N-19-9. Molecular weights and other general biochemical characteristics of serum mucin carrying the type 1 chain determinants were not significantly different in cancer patients as compared with patients with nonmalignant disorders. However, the degree of glycosylation of the antigen, as assessed by its solubility in perchloric acid, showed significant differences; i.e., the mucin antigen carrying 2----6 sialylated Lea determinant in the sera of patients with nonmalignant disorders had the highest carbohydrate/protein ratio, followed by the mucin carrying the same determinant in the sera of cancer patients. Mucin antigen carrying 2----3 sialylated Lea antigen or 2----3, 2----6 disialylated Lc4 antigen in cancer patients had the lowest carbohydrate/protein ratio among the four groups tested. Thus, the carbohydrate/protein ratio in the type 1 chain mucin antigens in sera of normal subjects is higher than that in sera of cancer patients (P less than 0.05). This finding is in contrast to previous findings on the mucin antigens carrying the type 2 chain determinant (R. Kannagi et al., Cancer Res., 46: 2619-2626, 1986), in which the mucin antigen in cancer patients was found to have a much higher carbohydrate/protein ratio than that carrying the same antigenic determinants in patients with nonmalignant disorders.     

90k is a serum marker of poor-prognosis in non-hodgkins-lymphoma patients

Monoclonal antibody SP-2, which binds to a 90,000 daltons tumor-associated antigen termed 90K, was generated by mouse immunization with proteins released by human breast cancer cells into the culture medium (Iacobelli et al: Cancer Res 46: 3005-3010, 1986). Elevated 90K levels have been previously reported in the serum of patients with various malignancies. We investigated whether the circulating levels of 90K antigen might be related to prognosis of patients with Non-Hodgkin's Lymphomas (NHL). Serum samples were obtained from 50 apparently healthy blood donors and 81 patients with NHL. Circulating serum 90K concentrations (U/ml) were determined by a solid-phase immunoradiometric assay (IRMA) by a two-step procedure. Serum 90K levels were significantly higher in patients with NHL than in healthy controls (p=0.004). The Kaplan-Meier analysis of overall survival showed that patients with 90K-negative (serum 90K levels less than or equal to 16 U/ml) survived longer than patients with 90K-positive sera (less than or equal to 16 U/ml) (p=0.004). Multivariate regression analysis revealed that serum levels of LDH and 90K were the two independent prognostic variables for predicting overall survival. We propose that an elevated 90K antigen level in sera is a predictor of poor prognosis in NHL.     

Quantitative and qualitative characterization of human cancer-associated serum glycoprotein antigens expressing fucosyl or sialyl-fucosyl type 2 chain polylactosamine

The quantity of tumor-associated antigens carrying type 2 chain polylactosamines with four types of fucosyl determinants, LeX (X-hapten), poly-LeX, sialyl LeX, and LeY (Y-hapten), present in sera of patients with various malignant and non-malignant disorders, as well as the qualitative chemical properties of the carrier molecules in sera, have been investigated using four monoclonal antibodies, each of which defines one of these determinants. The following findings are of particular importance: the serum levels of LeX defined by antibody FH2 and poly-LeX defined by ACFH18 in patients with cancer were occasionally high (incidence about 10%); however, the majority of patients did not show elevated levels; the serum level of the antigen, defined by monoclonal antibody FH6 (termed sialyl LeX-i since this determinant is carried by i antigen), was significantly high in patients with cancers originating from organs from which adenocarcinomas often develop. For example, among various types of lung cancer, only adenocarcinoma but not squamous cell carcinoma, small cell carcinoma, or large cell carcinoma showed a high level of sialyl LeX-i antigen in sera. The incidence of high antigen levels in sera of patients with adenocarcinomas of lung was as high as 76% of the observed cases; the serum level of Ley (Y-hapten) was frequently high in patients with hepatoma (incidence, 34%); sialyl LeX-i antigen was separated on gel filtration as a glycoprotein with an average molecular weight greater than 10(6). It was characterized by its susceptibility to basehydrolysis, Pronase digestion, and sialidase and endo-beta-galactosidase treatment and is assumed to be a high molecular weight mucin-type glycoprotein; sialyl LeX-i antigen expressed in sera of patients with cancer was soluble in perchloric acid, while the same antigen in sera of patients with noncancerous diseases and normal subjects was mostly insoluble in perchloric acid. LeX, a poly-LeX, and essentially all LeY antigens in sera of patients with cancer were perchloric acid-insoluble.     

Serum Soluble Interleukin-2 Receptor Levels in Patients with Adult T-cell Leukemia and Human T-cell Leukemia/Lymphoma Virus Type-I Seropositive Healthy Carriers

Using an enzyme-linked immunosorbent assay (ELISA) technique, we measured the soluble interleukin 2 receptor (s-IL-2R) levels in the sera of patients with adult T-cell leukemia (ATL) in Japan. The s-IL-2R levels in the sera of the ATL patients were markedly higher (range 540-310, 400 U/ml, mean ±SD=62,800 ±81,000 U/ml, n = 42) than those in normal individuals (range 42-950 U/ml, mean ±SD=322 ±198 U/ml, n = 35, P<0.01). The patients with acute-type or lymnhoma-type ATL had high s-IL-2R levels (range 11,900-310,400 U/ml, mean ±SD= 110,340 ± 370 U/ml, n = 15; range 26,400-214,400 U/ml, mean ±SD=90,170 ±59,040 U/ml, n = 7, respectively). All of the patients with hypercalcemia (Ca>10 mg/dl) or elevated serum LDH levels (LDH > 500 IU/liter) also had s-IL-2R levels above 10,000 U/ml. The high s-IL-2R levels in the sera of ATL patients indicate abnormal IL-2 receptor production and its release from the leukemic cells in vivo . Thus, the serum s-IL-2R level may be a sensitive and useful marker to monitor the total amount of tumor cells in ATL, especially in the lymphoma type. We next examined the serum s-IL-2R levels in human T-cell leukemia/lymphoma virus type-I (HTLV-I) seropositive healthy carriers to investigate whether there might he abnormal IL-2 receptor expression in such individuals. However, there was no statistically significant difference between the S-IL-2R level of 71 HTLV-I seropositive healthy carriers (range 65-880 U/ml, mean±SD =394±212 U/ml) and that of 71 age- and sex-matched normal individuals (range 33-950 U/ml, mean ±SD=357 ±224 U/ml) who lived in Okinawa Prefecture.     

Serum soluble interleukin-2 receptor levels in patients with adult T-cell leukemia and human T-cell leukemia/lymphoma virus type-I seropositive healthy carriers

Using an enzyme-linked immunosorbent assay (ELISA) technique, we measured the soluble interleukin 2 receptor (s-IL-2R) levels in the sera of patients with adult T-cell leukemia (ATL) in Japan. The s-IL-2R levels in the sera of the ATL patients were markedly higher (range 540-310, 400 U/ml, mean +/- SD = 62,800 +/- 81,000 U/ml, n = 42) than those in normal individuals (range 42-950 U/ml, mean +/- SD = 322 +/- 198 U/ml, n = 35, P less than 0.01). The patients with acute-type or lymphoma-type ATL had high s-IL-2R levels (range 11,900-310,400 U/ml, mean +/- SD = 110,340 +/- 370 U/ml, n = 15; range 26,400-214,400 U/ml, mean +/- SD = 90,170 +/- 59,040 U/ml, n = 7, respectively). All of the patients with hypercalcemia (Ca greater than 10 mg/dl) or elevated serum LDH levels (LDH greater than 500 IU/liter) also had s-IL-2R levels above 10,000 U/ml. The high s-IL-2R levels in the sera of ATL patients indicate abnormal IL-2 receptor production and its release from the leukemic cells in vivo. Thus, the serum s-IL-2R level may be a sensitive and useful marker to monitor the total amount of tumor cells in ATL, especially in the lymphoma type. We next examined the serum s-IL-2R levels in human T-cell leukemia/lymphoma virus type-I (HTLV-I) seropositive healthy carriers to investigate whether there might be abnormal IL-2 receptor expression in such individuals. However, there was no statistically significant difference between the s-IL-2R level of 71 HTLV-I seropositive healthy carriers (range 65-880 U/ml, mean +/- SD = 394 +/- 212 U/ml) and that of 71 age- and sex-matched normal individuals (range 33-950 U/ml, mean +/- SD = 357 +/- 224 U/ml) who lived in Okinawa Prefecture.     

Clinical significance of serum sialyl Tn antigen in patients with gynecological cancer. STN Study Group

Serum sialyl Tn antigen was assayed in gynecological cancer and benign patients by means of "STN OTSUKA" kits. Fifty-eight of 140 (41.1%) ovarian cancer patients showed a significant elevation of sialyl Tn antigen in serum above the cut-off level of 45 unit/ml (mean +2SD) determined from normal controls. There was no feature of positive frequency in tissue type, including serious carcinoma (47.6%), mucinous carcinoma (45.5%), clear cell carcinoma (30.4%) and endometrioid carcinoma (55.6%), but the positive frequency of mucinous carcinoma (36.8%) was higher than that of serous carcinoma (11.1%) in stage I. Compared with other markers, sialyl Tn antigen showed a very much lower false-positive rate (3.6%) in benign gynecological diseases. In the diagnosis of ovarian cancers, the combination assay of sialyl Tn antigen and CA 125 increased diagnostic efficiency compared with any other combination assays. Therefore, sialyl Tn antigen will be a useful tumor marker for ovarian cancers.     

Profiles of Lewisx-containing glycoproteins and glycolipids in sera of patients with adenocarcinoma

Oligosaccharides with Lex determinant (Gal beta 1----4[Fuc alpha 1----3]GlcNAc) are accumulated in large quantities in various adenocarcinomas. Monoclonal antibodies recognizing mono-, di-, or trimeric Lex showed a preferential staining of specific stages of human fetal tissues and various human adenocarcinomas. Thus, these carbohydrate epitopes are typical of oncodevelopmental antigens. The present study investigated the presence of Lex epitope in sera of normal individuals and cancer patients, utilizing two high-affinity monoclonal antibodies, SH1 and SH2, directed to mono- and dimeric Lex structures, respectively. The Lex antigen in serum was eluted in the void volume fraction of a gel filtration column, determined by using monoclonal antibody SH1, and found to be carried on a glycoprotein with a molecular weight of approximately 200,000. The Lex antigen was present in the void volume fraction of the majority (85%) of sera from adenocarcinoma patients. Although the Lex epitope was also detected in a smaller proportion (33%) of normal sera, its levels were significantly lower than in cancer sera. Lex antigen was also detected in serum glycolipid fraction; however, no significant differences were observed in normal and cancer sera. A double determinant solid phase immunoassay utilizing SH2 as the capture antibody and SH1 as the detecting antibody allowed direct determination of Lex levels in sera. By the use of this direct assay, the levels of serum Lex were found to increase in association with the progression of colorectal cancer (Dukes A to D). The percentage of detectability in sera from colon cancer patients was as follows: Dukes A, 20%; Dukes B, 45%; Dukes C, 67%; and Dukes D, 74%. The levels of serum Lex were also of prognostic value in Dukes C cancer patients after surgery and during postoperative follow-up.     

CA 15-3 is present as a novel tumor marker in the sera of patients with breast cancer and other malignancies

As a novel tumor marker, we employed a quantitative sandwich RIA system utilizing two monoclonal antibodies (115D8, DF3) which react with a circulating antigen expressed by human breast cancer cells. The optimum condition for this assay was found be a 60 minute incubation at 37 degrees C for the first reaction and a 60 minute one at 25 degrees C for the second reaction. Under these optimum conditions, intra-assay variation of control sera was CV 3.6% and inter-assay variation was CV 6.6%. The observed range of CA 15-3 concentration in 75 healthy persons was 7.5 +/- 3.4 units/ml (mean +/- SD) and mean +2 SD was 14.2 U/ml. Less than 15 U/ml was decided as the cut off level. The positive rate in 113 patients with benign diseases was 18%, the serum levels being less than 25 U/ml. Increased CA 15-3 levels in sera of 178 patients were found respectively, in 0%, 41%, 45%, 50% and 75% of stage I, II, III, IV in primary breast cancer and advanced breast cancer. The sera of 10 patients with advanced breast cancer were collected regularly during a 2 to 4 month period. All patients with PD showed increased CA 15-3 levels and four patients in PR showed a clear decrease of serum levels. In 167 other malignancies, increased levels were found in 76%, 63%, 58%, 33%, 32% and 22% of the sera from uterine, pancreatic, ovarian, prostatic, lung and gastric carcinomas. The data revealed that serum CA 15-3 was clinically useful as a tumor marker especially a monitoring marker of advanced breast cancer, but presently the assay is not suitable for the early detection of breast tumors. Also its measurement seemed to be useful in ovarian cancer, uterine cancer, pancreatic cancer and adenocarcinoma of the lung.     

A fundamental and clinical investigation of cancer antigen 130 (CA 130) in the field of obstetrics and gynecology

Two murine monoclonal antibodies designated 130-22 and 145-9 have been recently established by immunizing mice with a pulmonary carcinoma cell line (PC-9). With use of these monoclonal antibodies a sensitive sandwich immunoradiometric assay (IRMA) for cancer antigen 130 (CA130) was developed in Daiichi Radioisotope Laboratories (Tokyo). Applying this IRMA kit CA130 concentrations were measured in various body fluids with special reference to obstetrics and gynecology. The results are as follows; 1) A CA130-IRMA showed excellent sensitivity, specificity, reproducibility and analytical recovery. The standard dose-response curve covered the range from 10 to 500 U/ml. 2) Serum CA130 levels measured by this assay system were closely correlated with serum CA125 levels, demonstrating quite a high correlation coefficient (r = 0.965). 3) In pregnancy maternal CA130 levels increased moderately (less than 300 U/ml) in the first trimester, and thereafter fell rapidly under normal upper limit (less than 35 U/ml). Immediately after deliveries maternal CA130 levels showed a rapid increase, reaching 269 U/ml (mean levels). In amniotic fluids CA130 concentrations were greatly elevated (3,236 U/ml mean levels), while the levels were almost within normal limit in the umbilical arterial and venous blood. Accordingly it is necessary to measure Schwangerschaftsprotein 1 or human chorionic gonadotropin simultaneously with CA130 to rule out possible pregnancy. 4) CA130 was clearly localized in the amniotic epithelium and umbilical sheath and other placental tissue components remained negative for this antigen. Taking the lower CA130 levels in the umbilical sera into consideration, these immunohistochemical results suggest CA130 is not oncofetal but oncoplacental. 5) Serum CA130 levels increased pretherapeutically beyond 35 U/ml in 87% of ovarian malignancies, and in 56% of endometrial carcinoma. The mean levels of serum CA130 reached 931 and 143 U/ml, respectively. These data indicate clinical usefulness of CA130 as a tumor marker for those diseases. By contrast serum CA130 levels were lower, and very few cases showed serum CA130 levels over 35 U/ml in cervical cancer. 6) In endometriosis 88% of the cases demonstrated increased serum CA130 levels, indicating its usefulness for monitoring therapeutic courses, just like CA125. In benign gynecologic diseases over 80% of cases showed increased serum CA130 levels while only slight increase in serum CA130 was found (mean levels less than 84.0 U/ml). This disadvantage could be lessened by a combination assay with CA72-4 and others whose serum levels were very low in the benign diseases.     

Initial clinical evaluation of an immunoradiometric assay for CA 19-9 using the NCI serum bank

More than 1,600 coded sera obtained from blood donors and the NCI/Mayo Clinic Serum Bank were analyzed with an improved immunoradiometric assay for the carbohydrate antigenic determinant, CA 19-9. Results indicated that CA 19-9 is elevated in a large fraction of sera (67%) from patients with advanced adenocarcinomas of the upper gastrointestinal (GI) tract, including those with pancreatic, hepatobiliary and gastric carcinomas. Several of these sera had CA 19-9 exceeding 300,000 U/ml. A smaller fraction (18%) of patients with carcinomas of the large bowel had elevated serum CA 19-9 levels, the majority among patients with metastatic disease. In contrast, none of the healthy donors from the serum bank and only 4 of 1,023 of the blood donor specimens (0.4%) had CA 19-9 levels greater than or equal to 40 U/ml. Three of 235 sera (1.3%) from benign disease patients had levels of CA 19-9 in excess of 40 U/ml. These data suggest that the improved CA 19-9 immunoradiometric assay may have clinical utility as a diagnostic adjunct for adenocarcinoma of the upper GI tract and that the assay also may have some value in monitoring patients with advancing colorectal carcinoma, particularly in combination with CEA determinations. Rigorous prospective clinical trials will be necessary to verify these hypotheses.