Somatic activation of rasK gene in a human ovarian carcinoma.

A tumor isolate from a patient with serous cystadenocarcinoma of the ovary contained an activated rasK gene detected hy transfection of NIH/3T3 cells. In contrast, DNA from normal cells of the same patient lacked transforming activity, indicating that activation of this transforming gene was the consequence of somatic mutation in the neoplastic cells. The transforming gene product displayed an electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gels that differed from the mobilities of rasK transforming proteins in other tumors, indicating that a previously undescribed mutation was responsible for activation of rasK in this ovarian carcinoma.

Reactivity of a monoclonal antibody with human ovarian carcinoma.

A murine monoclonal antibody (OC125) has been developed that reacts with each of six epithelial ovarian carcinoma cell lines and with cryopreserved tumor tissue from 12 of 20 ovarian cancer patients. By contrast, the antibody does not bind to a variety of nonmalignant tissues, including adult and fetal ovary. OC125 reacts with only 1 of 14 cell lines derived from nonovarian neoplasms and has failed to react with cryostat sections from 12 nonovarian carcinomas.

Specificity of heteroantisera developed against purified populations of intact murine ovarian carcinoma cells.

Antisera were raised in New Zealand White rabbits against purified populations of murine ovarian carcinoma (MOT) cells that were freed from contaminating host leukocytes and erythrocytes. In contrast to other antisera raised against this tumor, heteroantisera from rabbits immunized with purified tumor cell suspensions consistently retained antitumor activity after exhaustive absorption with syngeneic (C3HeB/FeJ) adult and fetal tissues. Absorbed antisera inhibited tumor growth in vivo and reacted with MOT cells in vitro as judged by indirect immunofluorescence, binding of staphylococcal protein A, and complement-mediated cytotoxicity. Appropriately absorbed antisera failed to bind to fetal tissues or to adult spleen, ovary, and kidney cells. Antisera with similar specificity could be obtained with the use of populations purified on a fluorescence-activated cell sorter or on discontinuous rabbit serum albumin gradients. Optimal titers against tumor were raised with multiple injections of 5 x 10(5) gradient-purified MOT cells.

Interaction of monoclonal antibodies with cell surface antigens of human ovarian carcinomas.

Two monoclonal antibodies, OC 125 and OC 133, bind to distinct determinants on the surface of human epithelial ovarian carcinoma cell lines. OC 125 and OC 133 recognize determinants on molecules with molecular weights greater than 200,000 and 80,000, respectively. When binding to four different cell lines was compared, apparent affinity constants for OC 125 ranged from 3.1 X 10(9) to 6.0 X 10(7) M-1, whereas those for OC 133 ranged from 1.6 X 10(9) to 8.5 X 10(8) M-1. An estimate of the number of antigenic determinants per cell ranged from 1.0 X 10(7) to 2.8 X 10(5) for OC 125 and from 4.0 X 10(5) to 3.4 X 10(4) for OC 133. Antigenic determinants recognized by OC 125 and OC 133 could be detected in spent culture medium. When radiolabeled OC 125 was incubated with each of four ovarian tumor cell lines, approximately 90% of the antibody remained bound to the tumor cell surfaces for more than 20 hr. Similar binding of OC 133 was observed with three of the four ovarian tumor cell lines. By contrast, greater than 70% of OC 133 antibody was either shed or endocytosed after binding to OVCA 433 cells over the same period. Antigenic modulation was not induced by either antibody interacting with any of the four cell lines. These data suggest that antigen may be lost from the surface of human ovarian carcinoma cells by several different mechanisms and that antigen release is not inconsistent with binding of radiolabeled antibody to the tumor cell surface for prolonged periods.

Elimination of leukemic cells from rat bone marrow using antibody and complement.

An animal model has been developed that utilizes antibody and complement to eliminate a transplantable cloned line of Wistar/Furth acute nonlymphocytic leukemia (CI-3) from syngeneic Wistar/Furth bone marrow. The CI-3 leukemia grows progressively from an i.v. inoculum of 10(1) to 10(2) cells. Antiserum has been raised in rabbits following multiple injections of CI-3. Using optimal concentrations of absorbed antibody and complement, approximately 3 logs of tumor could be destroyed in vitro, judged by the number of cells required to produce progressive growth in vivo. Similar incubation with antibody and complement did not affect the ability of Wistar-Furth marrow to reconstitute rats that had received lethal total-body irradiation (950 R). Each of the 33 irradiated rats that received mixtures of 10(4) CI-3 and 1.6 X 10(8) nucleated bone marrow cells succumbed to leukemia within 65 days, whereas 16 of 33 rats (48%) receiving similar inocula that had been treated with antibody and complement survived greater than 180 days without evidence of tumor growth. Repeated treatment of contaminated marrow with antibody and complement following removal of mature granulocytes and erythrocytes on density gradients permitted elimination of 10(5) CI-3.

Unifocal origin of advanced human epithelial ovarian cancers.

Ovarian cancers are often diagnosed at a late stage, after the cancer cells have spread to extraovarian sites. Failure to diagnose these tumors earlier may reflect the lack of symptoms and the need for a sensitive, reliable screening test. Alternatively, this can be explained by the hypothesis that some of the extraovarian tumor implants do not represent metastatic spread from the primary cancer but instead are multiple primary tumors developing simultaneously in the peritoneal epithelium. If this is the case, some patients with advanced ovarian cancer may never have had a stage I disease, making early detection theoretically impossible. In this study, we examined the mutational pattern of the p53 gene in 9 patients with epithelial ovarian cancers using tissue collected from different sites within the same patient. In all 9 cases, the mutational pattern of the p53 gene was identical in cancer cells from different sites within the same patient, strongly suggesting that these ovarian tumors were of unifocal origin and that cancer tissues collected from different sites are derived from a single origin.

Monoclonal antibody immunoradiometric assay for an antigenic determinant (CA 125) associated with human epithelial ovarian carcinomas.

CA 125 is an antigenic determinant expressed by greater than 80% of nonmucinous epithelial ovarian carcinomas. An immunoradiometric assay has been developed using a murine monoclonal antibody (OC125) to quantitate CA 125 in human serum. This immunoradiometric assay was optimized for specificity, sensitivity, and performance characteristics. Using a simultaneous immunoradiometric assay, the mean CA 125 concentration in 56 sera from healthy individuals was 11.2 +/- 5.4 (S.D.) units/ml, with 9.7 +/- 3.2 units/ml for 30 males and 13.1 +/- 6.8 units/ml for 26 females. A reference value of 35 units/ml included all 56 normals and excluded 86 of 105 (82%) ovarian carcinoma patients. This reference value also excluded 9 of 142 patients (6%) with benign diseases, but if the upper limit of normal was set at 65 units/ml, only 3 of 142 (2%) patients with benign diseases had elevated serum CA 125 levels, whereas 77 of 105 (73%) ovarian carcinoma patient sera remained positive. The ability of researchers, with this assay, to discriminate between CA 125 values in sera of patients with ovarian carcinoma and those of healthy individuals and patients with benign disease suggests that the assay deserves continued evaluation for monitoring and early diagnosis of ovarian cancer.

Mutation of K-ras protooncogene in human ovarian epithelial tumors of borderline malignancy.

The mutation of K-ras protooncogene was examined in 44 cases of borderline ovarian epithelial tumors and 18 cases of invasive ovarian carcinomas. In borderline tumors, K-ras mutations are a common feature, having been found in 21 of 44 cases (48%). Twenty of the 21 mutations were identified at codon 12, and one was identified at codon 13. A detailed analysis of the mutation pattern of K-ras revealed a close association with the histological cell types of the tumor. Mutation of K-ras was detected at a higher frequency in mucinous borderline tumor (identified in 12 of 19 cases) compared to serous borderline tumor (identified in 9 of 25 cases). K-ras mutation was also detected in invasive mucinous and serous ovarian carcinomas, hence supporting the notion that borderline ovarian tumors may represent a pathological continuum between benign and frankly invasive diseases.

Intraperitoneal immunotherapy of human ovarian carcinoma with Corynebacterium parvum.

Corynebacterium parvum has been administered i.p. to 14 patients with advanced ovarian cancer. Two patients had responded completely to cytoreductive surgery and combination chemotherapy prior to immunotherapy, and one patient with residual disease had received only a single course of C. parvum due to i.p. catheter malfunction. Among the 11 patients with residual disease evaluable for response, from three to eight i.p. treatments with C. parvum produced surgically confirmed tumor regression in five patients (45%) with three partial responses and two complete responses of 5 and 12 months duration. All responders had (a) multiple tumor nodules less than 0.5 cm at the initiation of immunotherapy, and (b) severe abdominal pain and fever after C. parvum injection. Overall, 58 courses of immunotherapy were associated with abdominal pain (91%), fever (67%), nausea (52%), vomiting (31%), and hypotension that responded promptly to i.v. infusion of fluids (10%). Use of i.p. cathethers was associated with two episodes each of infection and intraabdominal bleeding. Administration of C. parvum i.p. has augmented the ability of human peritoneal cells to lyse human ovarian carcinoma cell lines in the presence of specific rabbit heteroantiserum. C. parvum administered i.p. has inhibited the growth of human ovarian carcinoma and may prove useful for modulating the activity of human effectors for antibody-dependent cell-mediated cytotoxicity.

Evidence for a multifocal origin of papillary serous carcinoma of the peritoneum.

Histopathological evidence suggests that papillary serous carcinoma of the peritoneum (PSCP) may be multifocal in origin. Utilizing a PCR based method to detect tandem repeat polymorphisms in formalin fixed tissue, loss of heterozygosity at eight loci on chromosomes 1, 3, 4, and 17 was studied in six cases of PSCP. Loss of heterozygosity was assessed at between 5 and 11 tumor sites/patient. Allelic losses at 4 loci (1q32-qter, 3p14.3-21.1, 17q12, 17q21.3-23) were noted. Three cases demonstrated a different pattern of allelic loss at various anatomic sites within the same patient. In an additional case, a mutation of the p53 gene, detected by quantitative PCR followed by single-strand conformation polymorphism analysis, was detected in only 2 of 5 tumor sites. The pattern of allelic loss and the mutational pattern of the p53 gene varied at tumor sites within the same patient in 4 of 6 cases of PSCP. These findings are consistent with histopathological evidence that PSCP is multifocal in origin.

An assay for the detection of human anti-murine immunoglobulins in the presence of CA125 antigen.

A radioimmunoassay for the detection of human immunoglobulin response is described which is suitable for the screening of patients undergoing immunotherapy with murine monoclonal antibodies. The use and the sensitivity of the assay are illustrated in the case of patients undergoing diagnostic imaging for ovarian cancer with the monoclonal antibody, OC125. The method offers the distinct advantage of quantitating human anti-murine antibody in serum containing a high concentration of antigen recognized by the injected murine antibody. In addition, the assay may be generalized to screen patients undergoing immunotherapy with a variety of murine or other monoclonal antibodies.

Analysis of cytotoxicity of 131I-labelled OC125 F(ab')2 on human epithelial ovarian cancer cell lines.

Monoclonal antibody (mAb) OC125 detects the cell surface-antigen CA125, which is expressed in more than 80% of epithelial ovarian cancers but not in normal adult ovaries. Its high specificity and binding affinity makes OC125 a potential candidate for use in radioimmunotherapy (RIT) in patients with recurrent ovarian cancer. Initial biodistribution studies using radiolabelled specific mAbs have demonstrated significant increase in tumor uptake of dose as compared to radiolabelled irrelevant antibody. We report here an isodose comparison of the cytotoxicity of 131I-labelled OC125 F(ab')2, 131I-labelled nonspecific protein and external beam irradiation using a cesium-137 gamma source. Enhancement of cytotoxity due to the specific binding of the mAb could only be observed when a critical activity of 131I localized at the cell membrane. At a specific activity labelling of less than 4.1 mCi/mg, the antigen specificity of OC125 does not contribute to cell kill. Using a specific activity of 10.2 mCi/mg, the relative biological effectiveness of 131I-labelled OC125 (F(ab')2 was increased by a factor of 5 compared with external-beam X-ray therapy, and the specificity of mAb OC125 was found to enhance the cytotoxicity of the radioimmunoconjugate (RIC) by a factor of 2.7. This low value is in accordance with previously reported theoretical calculations for long range, low-LET isotopes and may be one of the reasons why RIT using 131I has severe limitations. In conclusion, it is necessary to maximize the specific activity of RICs with low-LET isotopes such as iodine-131 in order to maximize the ratio of the dose delivered specifically by membrane-bound mAb versus free-floating nonspecific protein.

Immunopathologic characterization of a monoclonal antibody that recognizes common surface antigens of human ovarian tumors of serous, endometrioid, and clear cell types.

A murine monoclonal antibody, OC125, reacts with a surface component of ovarian tumor cells from humans, but fails to react with normal adult ovarian cells. The spectrum of reactivity of OC125 in ovarian tumors from humans was defined by testing cryostat tissue sections from 60 selected ovarian tumors by indirect immunofluorescence. OC125 stained 7/7 benign, and borderline serous ovarian tumors, 19/23 (83%) serous adenocarcinomas, 2/2 mixed serous and endometrioid carcinomas, 2/3 endometrioid carcinomas, 1/4 clear cell carcinomas, and 2/2 undifferentiated carcinomas. No reactivity was found in eight mucinous ovarian tumors or any of the other 11 epithelial sex cord, germ cell, on hematopoietic tumors tested. In neoplastic cysts, papillae, and glands, the staining was most intense on the luminal surface or in subjacent cytoplasm. Cells in solid sheets also showed peripheral staining. Within a reactive tumor, both negative and positive cells could be found, intimately intermixed. There were no differences in these staining patterns between tissues from primary and metastatic sites. The expression of the OC125 antigen was not related to the degree of malignancy as judged by pathologic criteria. Although mucinous tumors lacked reactivity with OC125, seven of eight mucinous adenomas and adenocarcinomas bound a monoclonal antibody against carcinoembryonic antigen (CEA). Thus, OC125 recognizes a common antigen in some but not all ovarian tumors of serous, clear cell, endometrioid, or undifferentiated type. OC125 may prove useful in the pathologic and cytologic identification of certain types of ovarian tumor cells. Its lack of reactivity with mucinous tumors suggests these belong in a distinct subgroup of ovarian epithelial tumors.

Review of epidemiologic studies of endometrial cancer and exogenous estrogen.

Epidemiologic literature on the association of exogenous estrogen and endometrial cancer is reviewed. Descriptive studies have documented fluctuations in the incidence of endometrial cancer, mainly of localized disease, associated with estrogen use. Etiologic studies have established an association between estrogen use during menopause and the occurrence of endometrial cancer. Although the association appears to be a valid one, several biases may have falsely increased the magnitude of this association. The association also appears to be strongest for local disease and weakest for the most invasive disease, which implies that the etiology for the more invasive endometrial cancers is largely unaccounted for by estrogen use. A need for a prospective study to define other potential risks and benefits of estrogen therapy is clear. However, appreciation of factors known to modify the risk of endometrial cancer from exogenous estrogen can help the clinician to use these preparations judiciously.

PIP: Controversy over the relationship between the use of exogenous estrogens and endometrial cancer persists and will be dissipated only by well designed prospective studies. Most epidemiological investigations, both descriptive and etiological, have reported a relationship between estrogen use and endometrial cancer, but the association may have been artifically inflated by a number of factors. The evidence for an association between less invasive forms of endometrial cancer and estrogen use is more convincing. Descriptive studies have reported an increase in the incidence of endometrial cancer in a number of regions in the U.S. from 1960 to the mid-1970s, and this observed increase has been attributed to the corresponding increase in estrogen usage during the same period. The high endometrial cancer rates may have been inflated by the inclusion of nonmalignant hyperplasia cases stemming from the recent adoption of more sensitive diagnostic criteria. The association between endometrial cancer and estrogen use revealed in a number of case control studies may have been exaggerated because: 1) cancer is more likely to be detected among women taking estrogens since they are under closer medical scrutiny; 2) women with a typical hyperplasia may have been assigned disease status; and 3) retrospectively ascertained medication records on women with cancer may be more complete than those obtained for controls. Prospective studies are needed to clarify the degree of association despite the high cost involved in this type of undertaking. In the meantime, it is suggested that clinicians in treating menopausal women 1) refrain from estrogen therapy if pretreatment endometrial biopsy findings indicate the presence of hyperplasia; 2) use low estrogen doses; 3) consider the addition of progesterone in the treatment regimen; and 4) perform yearly biopsies on women receiving treatment. Line graphs depict 1) duration of estrogen use by risk ratio of endometrial cancer and 2) comparison of cumulative risk of endometrial cancer by years of follow-up for a hypothetical 50 year old patient treated with estrogens and one not treated.

Sexual rehabilitation of gynecologic cancer patients.

The gynecologic oncologist's obligation encompasses more than cure or successful palliation of pelvic malignancy. The sexual rehabilitation of such patients is vital and must be done sensitively lest one's own concepts of "adequate sexuality" be imposed. Instruction in coital technics and alternative modes of sexual expression can be provided simply and effectively.

Endometrial stromal sarcoma arising from vaginal endometriosis.

The present case reports the concurrence of endometriosis of the vaginal cuff with endometrial stromal sarcoma in association with high-dose estrogen. This case raises the question of whether chronic high-dose estrogen might be associated with malignant transformation of endometrial stroma. Although there is no definitive evidence of a causal relation between estrogen and endometrial stromal sarcoma, the possibility should be explored further. Therapy of this neoplasm is discussed and salient clinical and pathologic features are reviewed.

Comparison of serum CA 125, clinical impression, and ultrasound in the preoperative evaluation of ovarian masses.

The ability to differentiate a malignant from a benign ovarian mass was assessed for four diagnostic procedures: serum CA 125, clinical examination, original ultrasound, and reviewer ultrasound interpretation. When these tests were used individually, the sensitivity and specificity of CA 125 levels were equal to those of a review ultrasound. Overall, the sensitivity of clinical impression and original ultrasound was poor. Sensitivity and specificity were highest for CA 125 assays in postmenopausal patients, especially when these were used as the second diagnostic test. Positive and negative predictive values significantly increased among postmenopausal patients when CA 125 was added to any of the other diagnostic tests examined. In conjunction with such tests, measurement of serum CA 125 significantly increased diagnostic accuracy and may thus have an important role in the preoperative evaluation of women with ovarian masses.

Serum CA 125 levels in a group of nonhospitalized women: relevance for the early detection of ovarian cancer.

Serum samples were collected from 915 nonhospitalized Roman Catholic nuns with a median age of 55 years (range 19-94 years). Using an immunoradiometric assay, serum CA 125 levels ranged from 0-574 U/mL with a median of 10.5 and mean of 14.3 U/mL. Thirty-six women (3.9%) had serum levels greater than 35 U/mL, and only seven (0.76%) had serum CA 125 levels above 65 U/mL. In only 14 (2.4%) of 586 women aged 50 or older were CA 125 levels above 35 U/mL, and in only three (0.51%) of this group did levels exceed 65 U/mL. Among the seven women with levels above 65 U/ML, five were found to have benign or malignant neoplasms or other masses at the time of entry into the study or during the follow-up interval (mean 311 +/- 103 days). Moreover, in six of seven members of this "false positive" group, some disorder was diagnosed during the study period that might have elevated the CA 125 level. No correlation was found between serum CA 125 levels and a variety of nonmalignant disorders or a variety of concurrent medications. The apparent specificity of the CA 125 assay in this study population suggests that, if used in conjunction with other tests to discriminate ovarian carcinoma from disorders that could elevate serum CA 125 levels, this assay might be a potential component of a strategy aimed at the early detection of ovarian cancer.

CA125 antigen levels in obstetric and gynecologic patients.

An immunoradiometric assay using a monoclonal antibody detects an antigenic determinant (CA125) that is present in more than 80% of epithelial ovarian cancers. CA125 levels are elevated in the sera of 16% of women in the first trimester of pregnancy and is found in very high concentration in amniotic fluid. In 988 nonpregnant patients with benign gynecologic disorders, CA125 was greater than 65 U/mL in 1% on a single determination and in 0.5% with two determinations. Given the low rate of positivity in benign gynecologic disease, the CA125 assay may deserve further evaluation for the early detection of ovarian carcinoma.

Preoperative evaluation of serum CA 125 levels in patients with primary epithelial ovarian cancer.

Serum CA 125 levels were measured preoperatively in 100 women undergoing diagnostic laparotomy for palpable adnexal masses. All 11 patients with frankly malignant nonmucinous ovarian carcinoma had serum CA 125 levels greater than 35 U/mL and nine of the 11 had serum CA 125 levels greater than 65 U/mL. If patients with mucinous and borderline lesions were included, serum CA 125 was greater than 35 U/mL in 11 of 18 and greater than 65 U/mL in nine of 18 patients. Among 14 individuals with pelvic masses and CA 125 greater than 65 U/mL, 13 had some form of gynecologic malignancy. These results suggest that CA 125 assay can be used as a diagnostic adjunct for discriminating benign from malignant pelvic masses.