Absence of premalignant histologic, molecular, or cell biologic alterations in prophylactic oophorectomy specimens from BRCA1 heterozygotes.

BACKGROUND: The high mortality associated with ovarian carcinoma is largely a reflection of the inability to diagnose the disease at an early stage; the identification of a histologic lesion or molecular marker associated early stages of transformation would represent an important advance in understanding the natural history of this cancer. The existence of individuals with germline mutations in the ovarian and breast carcinoma susceptibility gene BRCA1 represents a unique opportunity to search for such premalignant alterations in ovarian tissues that are at unusually high risk for tumorigenesis. In this study, the authors addressed the hypothesis that pathologically normal ovaries removed from BRCA1 heterozygotes are likely to display premalignant histologic, molecular, and/or cell biologic alterations that may provide insight into early stages of ovarian tumorigenesis. METHODS: Ovarian tissues from 18 BRCA1 heterozygotes and from 20 age-matched controls were examined in a blinded fashion for histologic evidence of surface epithelial pseudostratification, epithelial inclusion cysts, deep cortical invaginations of surface epithelium, increased stromal cell activity, and surface papillomatosis. Immunohistochemical analyses for expression of BRCA1, p53, and ERBB-2 and quantitation of cell proliferation (Ki-67 expression) and apoptosis (TUNEL assay), were also performed on all specimens. RESULTS: Although histologic alterations were observed, there was no difference in frequency between cases and controls. Analysis of BRCA1 expression revealed ubiquitous nuclear immunoreactivity in the surface epithelial cells of all ovaries. Similarly, no evidence was found of p53 overexpression in any ovarian tissue or of a difference in ERBB-2 expression between cases and controls. Finally, no differences were observed in epithelial cell proliferation or apoptosis. CONCLUSIONS: Clinically, normal ovaries from BRCA1 heterozygotes do not show evidence of premalignant alterations in histology, molecular markers, cell proliferation, or apoptosis, indicating that such changes are likely rare.

Clinicopathologic features of BRCA-linked and sporadic ovarian cancer.

CONTEXT: Most hereditary ovarian cancers are associated with germline mutations in BRCA1 or BRCA2. Attempts to define the clinical significance of BRCA mutation status in ovarian cancer have produced conflicting results, especially regarding survival. OBJECTIVE: To determine whether hereditary ovarian cancers have distinct clinical and pathological features compared with sporadic (nonhereditary) ovarian cancers. DESIGN AND SETTING: Retrospective cohort study of a consecutive series of 933 ovarian cancers diagnosed and treated at our institution, which is a comprehensive cancer center as designated by the National Cancer Institute, over a 12-year period (December 1986 to August 1998). PATIENTS: The study was restricted to patients of Jewish origin because of the ease of BRCA1 and BRCA2 genotyping in this ethnic group. From the 189 patients who identified themselves as Jewish, 88 hereditary cases were identified with the presence of a germline founder mutation in BRCA1 or BRCA2. The remaining 101 cases from the same series not associated with a BRCA mutation and 2 additional groups (Gynecologic Oncology Group protocols 52 and 111) with ovarian cancer from clinical trials (for the survival analysis) were included for comparison. MAIN OUTCOME MEASURES: Age at diagnosis, surgical stage, histologic cell type and grade, and surgical outcome; and response to chemotherapy and survival for advanced-stage (II and IV) cases. RESULTS: Hereditary cancers were rarely diagnosed before age 40 years and were common after age 60 years, with mean age at diagnosis being significantly younger for BRCA1- vs BRCA2-linked patients (54 vs 62 years; P=.04). Histology, grade, stage, and success of cytoreductive surgery were similar for hereditary and sporadic cases. The hereditary group had a longer disease-free interval following primary chemotherapy in comparison with the nonhereditary group, with a median time to recurrence of 14 months and 7 months, respectively (P<.001). Those with hereditary cancers had improved survival compared with the nonhereditary group (P=.004). For stage III cancers, BRCA mutation status was an independent prognostic variable (P=.03). CONCLUSIONS: Although BRCA-associated hereditary ovarian cancers in this population have surgical and pathological characteristics similar to those of sporadic cancers, advanced-stage hereditary cancer patients survive longer than nonhereditary cancer patients. Age penetrance is greater for BRCA1-linked than for BRCA2-linked cancers in this population.

Carcinosarcoma of the ovary in a patient with a germline BRCA2 mutation: evidence for monoclonal origin.

BACKGROUND: Themajority of hereditary breast and ovarian cancers are associated with germline mutations in BRCA1 or BRCA2. While the occurrence of breast carcinoma and epithelial ovarian carcinoma in association with BRCA mutations is firmly established, the etiologic role of these genes in the development of other tumor types is less well documented. Carcinosarcoma of the ovary is an uncommon tumor consisting of both malignant epithelial and malignant mesenchymal components. OBJECTIVE: Here we report a patient with an ovarian carcinosarcoma who was found to harbor a germline mutation in BRCA2. We sought to link the BRCA2 mutation to the pathogenesis of this tumor as well as to determine whether both histologic components arose from the same progenitor cell. METHODS: Microdissection and molecular genetic analyses of the carcinomatous and sarcomatous components of this tumor were performed. RESULTS: Clonal loss of the wild-type BRCA2 allele as well as the same somatic mutation of the TP53 gene was evident in both histologic components. CONCLUSIONS: These data indicate that hereditary ovarian carcinosarcoma may result from a mutation in BRCA2 and that both histologic elements of this tumor arose from the same progenitor cell.

Male breast cancer in the hereditary nonpolyposis colorectal cancer syndrome.

A male member of a large HNPCC kindred, affected by primary malignancies of the breast and colon, was identified. This individual was found to harbor a germline mutation of the MLH1 mismatch repair gene previously shown to segregate with disease in this kindred. The breast tumor exhibited somatic reduction to homozygosity for the MLH1 mutation, and microsatellite instability was evident in the breast tumor. We conclude that hereditary male breast cancer can occur as an integral tumor in the HNPCC syndrome.

Causes and consequences of microsatellite instability in endometrial carcinoma.

Genetic instability of microsatellite repeat sequences [microsatellite instability (MI)] is commonly seen in tumors associated with the hereditary nonpolyposis colorectal cancer syndrome and is a result of inactivating mutations in any of several genes involved in a particular pathway of DNA mismatch repair. Sporadic (i.e., nonhereditary) manifestations of several tumor types, including colorectal, gastric, and endometrial carcinomas, also exhibit MI in a significant fraction of cases. Many MI+ sporadic colorectal carcinomas are associated with somatic mutations of mismatch repair genes, and several genes with coding region microsatellites are frequently mutated as a result in these cancers. The molecular causes and consequences of MI in sporadic endometrial carcinomas remain obscure, however. The aims of this study were: (a) to identify a series of sporadic endometrial carcinomas with clear evidence of MI; (b) to determine the extent to which somatic alterations in mismatch repair genes are associated with this MI; and (c) to establish whether the genes containing coding region microsatellite repeats that are known to be disrupted in MI+ gastrointestinal cancers are also disrupted in MI+ endometrial carcinomas. Matched pairs of normal and tumor DNA from 57 consecutive cases of endometrial carcinoma were examined for evidence of MI using a consensus panel of microsatellite markers. Fourteen cases (25%) displayed unequivocal evidence of MI, consistent with previously published estimates of the incidence of MI+ sporadic endometrial carcinoma. These cases were subjected to a mutation screen of the coding regions and exon-intron boundaries of the mismatch repair genes MSH2 and MLH1. Although several polymorphisms were detected, no clearly deleterious mutations were found in either of these genes. Notably, however, hypermethylation of the MLH1 promoter region was identified in 10 of 14 (71%) MI+ cases. Somatic mutations in coding region microsatellite repeats in the TGFbetaIIR, IGFIIR, BAX, E2F4, MSH3, MSH6, BRCA1, and BRCA2 genes were generally rare. Four MI+ tumors (29%) contained somatic mutations in the PTEN gene, only one of which was likely the result of MI. These data indicate that somatic mutational inactivation of known mismatch repair genes does not account for the great majority of sporadic endometrial carcinomas with MI and that a significant fraction of these cases may instead be causally associated with hypermethylation of the MLH1 promoter. Furthermore, genes with coding region microsatellites that are frequently mutated in MI+ gastrointestinal cancers are rarely mutated in MI+ endometrial cancers, implying the existence of alternative molecular targets for the tumorigenic effects of MI in this tumor type.

Molecular genetic characterization of BRCA1- and BRCA2-linked hereditary ovarian cancers.

Hereditary ovarian cancers associated with germline mutations in either BRCA1 or BRCA2 were studied to determine whether somatic mutation of the P53 gene is required for BRCA-linked ovarian tumorigenesis and further, whether the spectrum of additional somatic molecular genetic alterations present in these tumors differs from that known to exist in sporadic ovarian cancers. Forty tumors, 29 linked to BRCA1 and 11 linked to BRCA2, were examined for mutational alterations in P53, K-RAS, ERBB-2, C-MYC, and AKT2. The presence of a P53 mutation in 80% of these cancers indicates that P53 mutation is common but not required for BRCA-linked ovarian tumorigenesis; notably, a significantly higher proportion of the P53 mutations in BRCA2-linked cancers were deletions or insertions compared with the more typical spectrum of missense mutations seen in BRCA1-linked cancers. Additionally, BRCA-linked ovarian carcinomas seem to develop through a unique pathway of tumorigenesis that does not involve mutation of K-RAS or amplification of ERBB-2, C-MYC, or AKT2.

Mutation analysis of the putative tumor suppressor gene PTEN/MMAC1 in primary breast carcinomas.

A novel gene was identified recently at chromosome 10q23, named PTEN or MMAC1, and based on several criteria it was designated as a potential human tumor suppressor gene. Loss of heterozygosity affecting this region of 10q is observed in several cancer types, especially glioblastoma, and inactivating mutations of the PTEN/MMAC1 gene are found in some of these cancers as well as cell lines and xenografts. Breast cancer is among the tumor types in which mutations are documented, and germline mutations of the gene appear to be responsible for the rare autosomal dominant familial cancer syndrome known as Cowden disease, which includes breast cancer among its clinical features. To further determine the role that PTEN/MMAC1 mutations may play in breast tumorigenesis, the entire coding region was screened for mutations in 54 unselected primary breast cancers. Two mutations were identified, a somatic 2-bp deletion in an apparently sporadic breast cancer, and a germ-line 4-bp deletion in a breast cancer patient with a clinical history consistent with Cowden disease. These data indicate that somatic mutations of PTEN/ MMAC1 occur in only a small fraction of primary breast cancers and confirm the role of this gene in the etiology of Cowden disease. Evidence is also presented suggesting that numerous polymorphisms and missense variants exist in the PTEN/MMAC1 transcript.

Distribution of radiolabeled monoclonal antibody MX35 F(ab')2 in tissue samples by storage phosphor screen image analysis: evaluation of antibody localization to micrometastatic disease in epithelial ovarian cancer.

Our objective was to quantify the targeting of the monoclonal antibody (mAb) MX35 F(ab')2 to micrometastatic epithelial ovarian cancer. This mAb detects a Mr 95,000 glycoprotein with homogeneous distribution on 80% of ovarian tumor specimens. Six patients with minimal residual disease from an imaging trial were injected with 2 or 10 mg of 131I- and 125I-labeled mAb MX35 F(ab')2. Biopsied samples were removed at second-look laparotomy 1-5 days post-i.v. or -i.p. infusion of antibody. Serial cryostat sections were stained by indirect immunoperoxidase method for antigen distribution and exposed to storage phosphor screens for quantitative autoradiography. Coregistration of tumor histology, antigen expression, and radionuclide distribution demonstrated specific localization in micrometastatic tumor foci (50 micrometer to 1 mm) found within tissue stroma. The radiolabeled antibody uptake determined by well scintillation counts ranged between 5.2 and 223.5 x 10(-4) percentage of injected dose/g of tumor tissue for 131I. Specific localization of mAb in tumor was determined by tumor:normal tissue (fat) ratios ranging from 0.9:1 to 35.9:1 for 131I. The high resolution and linear response of the storage phosphor screen imager was used to estimate the radionuclide activity localized in each micrometastatic site. Quantitation of phosphor screen response revealed microCi/g values of 0.026-0.341 for normal tissue and 0.184-6.092 for tumor biopsies, evaluated 4 or 5 days post-antibody injection. The tumor:normal tissue (adjacent to tumor) ratios were between 1 and 4 times greater using the phosphor screen method than well counter measurements, but even larger variations of ratios up to 20:1 were observed between tumor cell foci and stromal cells within the same tissue section. This study has demonstrated that mAb MX35 F(ab')2 localizes to the micrometastatic ovarian carcinoma deposits within the peritoneal cavity. The dosimetry results suggest a therapeutic potential for this antibody in patients with minimal residual disease (<5 mm).

Expression of A, B, and H blood group antigens in epithelial ovarian cancer: relationship to tumor grade and patient survival.

The expression of A, B, and H blood group antigens in epithelial ovarian cancer was evaluated in 137 patients with advanced disease by staining frozen sections with specific monoclonal antibodies using an indirect immunoperoxidase method. Expression of blood group antigens was observed in a proportion of ovarian carcinomas and in some areas of ovarian surface epithelium. Forty-eight percent of the tumors tested from 130 blood group A, B, or 0 individuals showed no expression of the appropriate blood group antigen, 32% had heterogeneous antigen expression, and 20% had strong expression. In the 7 blood group AB patients studied, no expression, heterogeneous expression of both antigens, or absence of one, but not the other antigen, was observed. No tumor showed A, B, or H antigen expression that was not compatible with the patient's blood group type. Histologic Grade 3 tumors showed absence of blood group antigen expression more often than did Grade 2 tumors. The presence or absence of A, B, or H antigen expression did not correlate with survival in this group of patients. This is in contrast to studies in other epithelial tumor types in which the normal epithelium synthesizes blood group antigens and loss of ABH antigen expression is observed in the corresponding tumors.

Serological and immunochemical analysis of Lewis y (Ley) blood group antigen expression in epithelial ovarian cancer.

The expression of Ley blood group antigen in epithelial ovarian cancer tissues and cell lines has been studied using a Ley-specific monoclonal antibody (MAb 3S193). In ovarian cancer specimens, Ley was expressed in 75% of the 140 tumor specimens examined, with strong or moderate expression being observed in 56% of the samples. Seven of the 11 ovarian cancer cell lines studied were Ley-positive. Using immunochemical approaches, Ley epitopes were found to be expressed on 4 types of carrier molecules: CA125 ovarian cancer antigen, MUC-1 mucins, lower m.w. glycoproteins and glycolipids. In cell lines, Ley was more commonly expressed on MUC-1 mucin than on CA125, whereas in tumor specimens Ley was commonly found on both CA125 and MUC-1. The biochemical nature of the smaller Ley glycoproteins was not determined, but it was shown that they were not CEA and LAMP-1, known Ley carriers in some other tumor types. Glycolipids carrying Ley epitopes were detected in both ovarian cancer cell lines and tumor specimens. The presence of Ley epitopes on a number of different molecular carriers, including 2 major ovarian cancer antigens (CA125 and MUC-1), explains the high incidence of Ley in ovarian cancer. The high expression of Ley in ovarian cancer and the availability of specific murine and humanized MAbs make Ley an attractive candidate target for clinical studies.

Interleukin-6 level in serum and ascites as a prognostic factor in patients with epithelial ovarian cancer.

BACKGROUND: Interleukin-6 (IL-6) is a multifunctional cytokine that can be produced by human ovarian cancer cells. Elevated IL-6 levels have been found in the serum and ascites of patients with ovarian cancer, but its role in this disease has not been clearly established. METHODS: The authors studied the relationship between IL-6 levels in serum and ascites, various tumor parameters, and survival in 70 patients with newly diagnosed, untreated epithelial ovarian cancer. Ascites and serum specimens were obtained at the time of initial surgery, and IL-6 levels were determined using the B9 bioassay. RESULTS: All patients underwent platinum-based chemotherapy after initial surgery. The median age of the group was 62 years (range, 28-87 years), and the median follow-up time was 13 months (range, 12-59 months). Significantly higher IL-6 levels were detected in patients' ascites (median, 49,612 pg/ml [range, < 1 to 680,330 pg/ml]) compared with serum (median, 10 pg/ml [range, < 1 to 1221 pg/ml]) (P < 0.0001). IL-6 levels in ascites correlated significantly with the volume of ascites (P < 0.0001) and nearly so with the size of tumor found at initial surgery (P = 0.05). Serum and ascites IL-6 levels did not correlate statistically with overall survival time, tumor stage, grade, histologic findings, residual tumor volume after debulking, and serum CA 125 levels. Although not statistically significant, patients who responded to chemotherapy tended to have lower ascites IL-6 levels (median, 21,102 pg/ml) compared with patients who did not respond to chemotherapy (median, 40,200 pg/ml). CONCLUSIONS: IL-6 is present in very high amounts in the ascites of patients with epithelial ovarian cancer. IL-6 levels in ascites correlated significantly with ascites volume and initial tumor size. IL-6 levels in ascites and serum did not correlate statistically with other tumor parameters or with survival time.

Prevalence and significance of HER-2/neu expression in early epithelial ovarian cancer.

BACKGROUND: Although expression of the HER-2/neu oncogene may be of some prognostic importance in advanced ovarian cancer, its role in early-stage disease has not been established. The current study examined the prevalence and significance of HER-2/neu expression in early epithelial ovarian cancer. METHODS: The authors analyzed the expression of HER-2/neu on frozen tumor specimens from 40 patients with early epithelial ovarian cancer using the indirect immunoperoxidase technique with monoclonal antibodies that detect epitopes on the extracellular domain of the HER-2/neu protein. All patients underwent comprehensive surgical staging. HER-2/neu expression was graded as negative, weak, moderate (1+ to 2+), or strong (3+). Complete clinical data and long-term follow up were available for all patients. RESULTS: The distribution of patients by stage was as follows: Stage IA, 6; IB, 0; IC, 14; IIA, 4; IIB, 6; IIC, 10. The mean patient age was 53 years. Fourteen patients had serous tumors; nine, endometrioid; eight, clear cell; eight, mucinous; and one, undifferentiated. Intratumoral heterogeneity of HER-2/neu expression was observed with most specimens. In eight specimens (20%), some areas of the tumor showed strong (3+) expression, beyond the level that can be seen in normal ovarian epithelium. Twenty-eight specimens (70%) showed moderate (1+ to 2+) staining, whereas four specimens (10%) showed negative or weak staining. At a mean follow-up time among surviving patients of 32 months, 15 patients (37%) have had cancer recurrence. No statistically significant relationship was found between HER-2/neu expression and survival, disease-free survival, stage, or grade. A significant increase was found in 3+ expression of HER-2/neu in clear cell tumors. CONCLUSION: Consistent HER-2/neu overexpression occurs infrequently in early ovarian cancer, making it unlikely that such overexpression is a general early event in ovarian carcinogenesis. HER-2/neu expression does not appear to be a strong prognostic marker in early epithelial ovarian cancer.

Biodistribution and intraoperative evaluation of radiolabeled monoclonal antibody MX35 in patients with epithelial ovarian cancer.

Murine monoclonal antibody (MAb) MX 35 shows strong homogeneous reactivity with more than 90% of epithelial ovarian cancers. Twenty-five patients with advanced ovarian cancer were entered into a clinical trial using 125I- or 131I-labeled MX 35 in doses of 2, 10, or 20 mg administered by intravenous (i.v.) or intraperitoneal injection. All patients underwent laparotomy at 7 to 20 days following MAb injection to assess tumor distribution, obtain biopsies of tumor and normal tissue, and evaluate the use of an intraoperative hand-held gamma-detecting device. Following i.v. injection, serum Mab half-life was 36 hr. Tumor biopsies obtained at surgery showed MAb accumulation of from 6.7 x 10(-3) to 4.0 x 10(-5)% injected dose/g of tissue. There was no correlation between absolute MAb accumulation in tumor and MAb dose administered. Regression analysis showed a correlation between MAb accumulation and the interval between MAb injection and surgery (P = 0.008). Specific localization of MAb in tumor was demonstrated by tumor:normal tissue ratios ranging from 2.3:1 to 34:1 (mean, 10.18:1). The tumor:normal tissue ratios were not significantly related to MAb dose, the level of immunohistochemical antigen expression, or the interval between MAb injection and surgery. Due to the relatively long serum half-life, mean tumor:serum ratios were only 1.53 following IV injection. This ratio did not correlate with MAb dose, days from injection, or antigen expression. There was an excellent correlation (P = 0.001) between MAb uptake, as measured by the intraoperative hand-held gamma counter, and direct gamma counting of excised tissues. MAb MX 35 localizes well to tumor in selected patients with ovarian cancer, and MAb uptake can be reliably quantitated in vivo with the hand-held intraoperative gamma counter.

Comparison of antigen expression on fresh and cultured ascites cells and on solid tumors of patients with epithelial ovarian cancer.

The antigenic phenotype of malignant cells from ascites of patients with epithelial ovarian cancers was examined and compared to that of their primary and metastatic sites. Cell-surface antigens on frozen sections of primary and metastatic tumors and frozen cell pellets from ascites were analyzed with a panel of murine monoclonal antibodies using the indirect immunoperoxidase method. In addition, ascites cells cultured with and without autologous cell-free ascitic fluid were evaluated by immunofluorescence. The pattern of antigen expression detected on fresh and cultured ascitic epithelial cells was shown to be identical to the expression in autologous solid tumor tissues. When placed in culture, malignant epithelial cells generally persisted for a minimum of one, but no more than five, passages. Addition of autologous ascitic fluid to cultures of ascites cells did not alter the phenotype of the epithelial tumor cell population and did not enhance the growth of these cells. From one culture of ascites cells a permanent malignant epithelial ovarian cancer cell line (designated SK-OV-8) was established. The demonstration that epithelial tumor cells found in ascites of patients with epithelial ovarian cancer have the identical antigenic phenotype as their solid tumor counterpart, at least for the panel of antigens studied, may be useful in planning imaging and therapeutic trials with monoclonal antibodies.

High IL-6 levels in ascitic fluid correlate with reactive thrombocytosis in patients with epithelial ovarian cancer.

Non-haematopoietic malignancies are commonly associated with thrombocytosis. The aetiology of tumour-associated thrombocytosis is still unclear but may be related to tumour-derived thrombopoietin-like factors. Epithelial ovarian tumour cells have been shown to release IL-6 in vitro and high IL-6 levels have been identified in ascites of patients with ovarian cancer. Since IL-6 is a potent stimulator of megakaryocytopoiesis we examined IL-6 production at the tumour site and its relationship to serum IL-6 levels and circulating platelet counts in patients with ovarian cancer. Forty patients undergoing exploratory laparotomy for epithelial ovarian cancer [stage I+II: 6 (15%); stage III: 25 (62.5%); stage IV: 9 (22.5%)] and 24 women with benign ovarian conditions were evaluated. Sera were available from 39 cases with ovarian cancer and from 19 cases with benign ovarian tumours. Ascites was obtained from 35 patients with ovarian cancer. IL-6 activity in serum and ascitic fluid was determined by the standard B9 proliferation assay (detection level: 1 pg/ml). IL-6 bioactivity was detectable in 22 (56%) sera from patients with ovarian cancer, but in only five (26%) of the serum samples obtained from benign cases (P < 0.001). Serum IL-6 levels in patients with ovarian cancer were significantly higher (median 3 pg/ml; range < 1 to 1221 pg/ml) than in patients with benign ovarian conditions (median 0 pg/ml; range < 1 to 4 pg/ml) (P < 0.001). However, much higher concentrations of IL-6 were measured in malignant ascites specimens (median 22,100 pg/ml; range < 1 to 182,600 pg/ml). IL-6 bioactivity in serum and ascites samples was completely inhibited by a neutralizing goat anti-human IL-6 antiserum. Thrombocytosis (platelet counts > 400 x 10(9)/l) occurred in 25 (62.5%) of the 40 patients with ovarian cancer, but in only two (8%) of the 24 cases with benign ovarian tumours. In eight (20%) cases with malignant disease platelet counts ranged between 600 x 10(9)/l and 1060 x 10(9)/l. IL-6 bioactivity in ascitic fluid correlated significantly with circulating platelet counts (r = 0.5916; P < 0.001). Maximum IL-6 bioactivity in ascites and highest platelet counts occurred in patients with undifferentiated ovarian adenocarcinoma or advanced disease. In conclusion, these observations strongly suggest a role for IL-6 in the development of tumour-associated thrombocytosis.

High-resolution positron emission tomography of human ovarian cancer in nude rats using 124I-labeled monoclonal antibodies.

PET has inherently high resolution and excellent contrast imaging and accurately measures radioactivity concentrations in vivo. When combined with specific immunological targeting it might provide a highly specific and sensitive radioimmunoscintigraphic tool. To investigate this we injected 124I-labeled MAb MX35 or MAb MH99 monoclonal antibodies (doses 200-400 mu Ci) intravenously into nude rats bearing subcutaneous human ovarian cancer xenografts (SK-OV-7 and SK-OV-3 cell lines). A melanoma cell line (SK-MEL-30) was used as a control tumor. These murine monoclonal antibodies react with cell-surface antigens expressed by most ovarian cancer cells, including the ovarian cell line used. Imaging was performed at 1-6 days using a high-resolution positron emission tomograph (PCR-I) with a spatial resolution of 4.5 mm. The slice thicknesses were 0.5 and 1.0 cm. Forty to seventy thousand coincident pulses were obtained per frame. The PET results were compared with those of autopsy and histology. Samples of blood, tumor, and normal tissues were obtained at various time points. PET calculation of isotope uptake ratios demonstrated specific localization of the antibodies in tumor, with ratios of tumor to normal tissue uptake as high as 6:1. Subcutaneous ovarian cancer nodules as small as 7 mm were identified with PET imaging. The results corresponded well with tissue sampling. Our findings suggest that PET imaging of tumors with 124I-labeled monoclonal antibodies may be useful in human diagnostic and therapeutic applications in ovarian cancer as well as other diseases.

Characterization of a human endometrial carcinoma cell line producing intraperitoneal tumor growth in immunodeficient mice.

Establishment of laboratory models of gynecologic neoplasms provides an important means of studying the biologic characteristics of these tumors. We report a previously uncharacterized human endometrial adenocarcinoma cell line that produces both intraperitoneal and subcutaneous growth in nude mice. The line was derived from a poorly differentiated endometrial cancer and has been carried in continuous tissue culture for greater than 100 passages. Doubling time in culture is approximately 48 hr. Antigenic phenotyping against a panel of murine monoclonal antibodies by rosetting cell surface assay on live cells or peroxidase assay on fixed cells has shown reactivity with a number of determinants, including MH99, MT334, MQ49, and the blood group antigens F3, 118, and 41-83. Cytogenetically, the line displays an aneuploid human karyotype with several chromosomal rearrangements and deletions. When injected intraperitoneally into nude mice, animals develop intraperitoneal nodules and ascites and succumb with wasting in 30-40 days. The intraperitoneal tumor has been passaged multiple times in nude mice by direct transfer of ascites. Subcutaneous injection of tumor cells produces nodules that grow at a reproducible rate. By light and electron microscopy, the nude mouse tumor is a poorly differentiated adenocarcinoma, similar to the original patient's tumor. It expresses both estrogen and progesterone receptors. CA 125 is not elevated in the serum of animals with tumor implants. The line appears to be cisplatin sensitive as determined by rates of growth of subcutaneous nodules. This cell line may be useful in studying the in vitro and in vivo properties of human endometrial carcinoma.

Some monoclonal antibody reagents (C219 and JSB-1) to P-glycoprotein contain antibodies to blood group A carbohydrate determinants: a problem of quality control for immunohistochemical analysis.

Monoclonal antibodies (MAb) C219 and JSB-1 have been used extensively in the analysis of P-glycoprotein expression in normal and malignant tissues. This study demonstrates that some commercial lots of these MAb, even those supplied as purified immunoglobulins, contain contaminating anti-A blood group antibodies. In both sources of reagent, the antibody was specific for a particular A structure, known as repetitive or Type 3 A. These observations may account for earlier studies showing polymorphic variation in P-glycoprotein expression in epithelial tissues and an apparent correlation with the A blood type of the donor. Such reactivity can be eliminated by absorption of anti-P-glycoprotein reagents with A erythrocytes. These data re-emphasize the importance of evaluating MAb samples for unsuspected contaminating antibodies.

Analysis of antigen expression at multiple tumor sites in epithelial ovarian cancer.

The question of whether the antigenic phenotype of human epithelial ovarian cancer varies in a given patient between the primary tumor and metastatic sites or among metastatic sites themselves is an important issue in planning potential therapeutic strategies for ovarian cancer. We have obtained tumor specimens from at least two separate sites during operations on 12 patients with epithelial ovarian cancer, and we have typed these specimens with a group of 18 monoclonal antibodies that react with cell-surface glycoprotein and carbohydrate antigens, including blood group antigens. Antibodies with relative specificity for malignant cells as well as those that detect more widely distributed epithelial antigens were used. A total of 31 specimens from 12 patients with advanced adenocarcinoma (8 serous, 3 undifferentiated, 1 endometrioid) of the ovary were studied, including fresh ascites cells in two patients. Frozen sections of tumor specimens were stained with the antibodies by the indirect immunoperoxidase technique and graded semiquantitatively. Little difference was seen in antigenic expression of tumors that were obtained from various sites in the same patient for either the epithelial cell markers or blood group markers. Intratumoral antigenic heterogeneity was seen, but this was generally quite consistent within a given patient's specimens. As anticipated, variations in antigen expression were seen among specimens from different patients. The antigenic phenotype of the tumor specimens in a given patient, as determined immunohistochemically by our group of antibodies, showed only minor variation among primary and metastatic sites.