Detection of mammaglobin in the sera of patients with breast cancer

Current procedures for the diagnosis of breast cancer are cumbersome and invasive, making detection of this disease difficult. A rapid screening test for early detection of breast cancer would allow for better management of this deadly disease. In this report, we show that, with the exception of the skin, mammaglobin mRNA is specifically expressed in mammary tissue and commonly overexpressed in breast cancer. Mammaglobin is not expressed in other types of cancer including colon, lung, ovarian, and prostate cancer. Breast-specific expression of mammaglobin protein was shown using immunohistochemical methods. Mammaglobin is secreted from both established breast cancer cell lines and primary breast carcinoma cells cultured in vitro. Using a monoclonal antibody-based assay for monitoring the presence of mammaglobin in serum, elevated levels of mammaglobin were detected in sera of patients with breast cancer, but not in healthy women. Thus, mammaglobin, which is overexpressed and secreted from breast carcinoma cells, is detectable in sera of patients with breast cancer and may provide a rapid screening test for the diagnosis and management of breast cancer.

Wide spectrum screening keratin as a marker of metaplastic spindle cell carcinoma of the breast: an immunohistochemical study of 24 patients

AIMS

Metaplastic spindle cell carcinomas may be difficult to distinguish histologically from other spindle cell lesions in the breast. Variable staining with cytokeratin immunomarkers has been reported for metaplastic carcinomas. We evaluated the diagnostic utility of anti-cytokeratin polyclonal antibody, wide spectrum screening keratin, to assess spindle cell breast lesions.

METHODS AND RESULTS

Twenty-four patients with spindle cell breast carcinoma and 31 patients with benign or malignant spindle cell tumours were studied using a panel of antibodies directed against multiple cytokeratins (AE1/AE3, CAM5.2, wide spectrum screening keratin), epithelial membrane antigen (EMA), and vimentin. Sites of origin for the 31 controls included breast, bone, and soft tissue. All but one (95.8%) metaplastic carcinomas stained positively with wide spectrum screening keratin. Only rare or focal immunoreactivity was observed with AE1/AE3 in four cases; however, sensitivity of AE1/AE3 was improved in 13 cases using steam EDTA as an antigen retrieval technique. Three cases were immunoreactive with CAM5.2 and eight cases were immunoreactive with EMA. All control cases lacked immunoreactivity with the cytokeratin panel and EMA. The spindle cells in the metaplastic breast tumours (88%) and in the controls (97%) stained with vimentin.

CONCLUSIONS

Wide spectrum screening keratin may be the most useful and convenient antibody in differentiating metaplastic spindle cell carcinoma from other spindle cell lesions in the breast.

Ontogeny of Phex/PHEX protein expression in mouse embryo and subcellular localization in osteoblasts

PHEX, a phosphate-regulating gene with homologies to endopeptidases on the X chromosome, is mutated in X-linked hypophosphatemia (XLH) in humans and mice (Hyp). Although recent observations indicate that Phex protein is expressed primarily in bone and may play an important role in osteoblast function and bone mineralization, the pattern of the Phex protein expression in the developing skeleton and its subcellular localization in osteoblasts remain unknown. We examined the ontogeny of the Phex protein in the developing mouse embryo and its subcellular localization in osteoblasts using a specific antibody to the protein. Immunohistochemical staining of mouse embryos revealed expression of Phex in osteogenic precursors in developing vertebral bodies and developing long bones on day 16 postcoitum (pc) and thereafter. Calvaria from day 18 pc mice showed Phex epitopes in osteoblasts. No Phex immunoreactivity was detected in lung, heart, hepatocytes, kidney, intestine, skeletal muscle, or adipose tissue of mouse embryos. Interestingly, embryonic mouse skin showed moderate amounts of Phex immunostaining. In postnatal mice, Phex expression was observed in osteoblasts and osteocytes. Moderate expression of Phex was seen in odontoblasts and slight immunoreactivity was observed in ameloblasts. Confocal microscopy revealed the presence of immunoreactive PHEX protein in the Golgi apparatus and endoplasmic reticulum of osteoblasts from normal mice and in osteoblasts from Hyp mice transduced with a human PHEX viral expression vector. PHEX protein was not detected in untransduced Hyp osteoblasts. These data indicate that Phex protein is expressed in osteoblasts and osteocytes during the embryonic and postnatal periods and that within bone, Phex may be a unique marker for cells of the osteoblast/osteocyte lineage.

PTEN induces chemosensitivity in PTEN-mutated prostate cancer cells by suppression of Bcl-2 expression

The tumor suppressor gene PTEN (MMAC1/TEP1) is lost frequently in advanced prostate cancer (PCa). However, the function of PTEN in tumorigenesis is not understood fully. In this study, we demonstrate that expression of Bcl-2 in prostate tumors correlates with loss of the PTEN protein. This finding was verified by studies in the PCa cell lines DU145, PC-3, LNCaP, and an androgen-refractory subline of LNCaP. Transient transfection of PTEN into the PTEN-null cells resulted in decreased levels of Bcl-2 mRNA and protein. These effects appear to be mediated at the level of gene transcription, since a Bcl-2 promoter-reporter construct was down-regulated by ectopic expression of PTEN in LNCaP cells. The inhibition of Bcl-2 required the lipid-phosphatase activity of PTEN and was blocked by overexpression of a constitutively active form of Akt. Moreover, the transcription-regulatory protein cAMP-response element-binding protein (CREB) may be involved, since decreased phosphorylation of CREB at Ser(133) was detected following PTEN expression, and ectopic expression of CREB repressed completely the PTEN-induced inhibition of Bcl-2 promoter activity. Furthermore, cotransfection of Bcl-2 and PTEN expression vectors rescued PTEN-induced cell death but not G(1) cell cycle arrest. Finally, forced expression of PTEN sensitized LNCaP cells to cell death induced by staurosporine, doxorubicin, and vincristine, and this chemosensitivity was attenuated by exogenous expression of Bcl-2. Taken together, these data demonstrate that loss of PTEN leads to up-regulation of the bcl-2 gene, thus contributing to survival and chemoresistance of PCa cells. These findings suggest that the PTEN gene and its regulated pathway are potential therapeutic targets in prostate cancer.

hMLH1 and hMSH2 expression in human hepatocellular carcinoma

The role of microsatellite instability (MSI) in the pathogenesis of hepatocellular carcinoma (HCC) is incompletely defined. Although high-frequency MSI (MSI-H) is infrequently seen in HCC, some studies have suggested a role for MSI in HCC development. While MSI has been clearly defined for a subset of tumors, in particular colorectal, gastric and endometrial cancers, generally accepted criteria have not been developed for other tumors. Colorectal cancers (CRC) are classified as MSI-H if >30-40% of >5 microsatellite loci analyzed show instability. The MSI-H phenotype is associated with defective DNA mismatch repair (MMR) and is observed in the majority of tumors from patients with hereditary non-polyposis colon cancer (HNPCC) and also in 15% of sporadic CRCs. Inactivating mutations of the hMLH1 or hMSH2 genes lead to defects in MMR in HNPCC. In sporadic CRCs, MMR is usually due to hypermethylation of the hMLH-1 promoter. The role of defective MMR in hepatocellular carcinogenesis is controversial. Immunohistochemistry for hMLH1 and hMSH2 reliably indicates hMLH1 or hMSH2 loss in MSI-H CRC tumors. To investigate the role of defective MMR in HCC carcinogenesis, we performed immunohistochemistry for hMLH1 and hMSH2 on 36 HCCs. BAT26, a microsatellite marker that reliably predicts MSI-H was also examined. All 36 of the tumors stained positively for both hMLH1 and hMSH2, strongly suggesting an absence of either inactivating mutations of hMLH1 and hMSH2 or promoter hypermethylation of hMLH1. None of the tumors showed MSI at the BAT26 locus. These findings suggest that defective MMR does not contribute significantly to hepatocellular carcinogenesis.

Analysis of Hurthle cell neoplasms of the thyroid by interphase fluorescence in situ hybridization

Recent studies have indicated that numerical chromosomal abnormalities including changes in p53 and cyclin D1 may be involved in Hurthle cell tumorigenesis. We analyzed a series of Hurthle cell neoplasms of the thyroid to evaluate the diagnostic and prognostic utility of numerical anomalies by DNA fluorescent probes for cyclin D1 and p53 gene loci and chromosomes 5, 7, 11, 12, 17, and 22. Interphase fluorescence in situ hybridization (FISH) analysis was performed on paraffin-embedded tissue sections from 10 Hurthle cell adenomas, 19 Hurthle cell carcinomas, and 7 normal thyroid tissues used as controls. Directly labeled fluorescent DNA probes for the centromere region of chromosomes 7, 11, 12, and 17 and locus-specific probes for chromosomes 5 and 22, cyclin D1, and p53 were utilized for dual-probe hybridizations. Sixty percent (6 of 10) Hurthle cell adenomas and 63% (12 of 19) Hurthle cell carcinomas showed chromosome gains. Twenty percent (2 of 10) Hurthle cell adenomas and 26% (5 of 19) Hurthle cell carcinomas showed chromosome losses. Normal thyroid tissues used as controls showed no chromosomal abnormalities. Among Hurthle cell tumors with chromosomal abnormalities, adenomas averaged 2.7 gains and 0.3 losses per case, and carcinomas averaged 3.3 gains and 0.6 losses per case. The two adenomas with chromosome losses each showed loss of one chromosome, whereas the five carcinomas with losses averaged 1.8 losses per case. Chromosome 22 was the most common loss identified, occurring in three of the 11 patients who died of disease. These results indicate that chromosomal imbalances as gains are common in both benign and malignant Hurthle cell neoplasms, but Hurthle cell carcinomas tend to have more chromosome losses than adenomas. Among Hurthle cell carcinomas in this study, chromosome losses were identified only from patients who died of disease. The loss of chromosome 22 may have prognostic value in Hurthle cell carcinoma of the thyroid.

Structural analysis of the 17q22-23 amplicon identifies several independent targets of amplification in breast cancer cell lines and tumors

A novel region of amplification in breast tumors has recently been identified on chromosome 17q22-23. In an effort to identify the oncogenes in the region that are targeted by the amplification process, we determined the structure of the amplicon in breast cancer cell lines and tumors. Physical and transcription maps of the approximately 3.5-Mb region were established and used as the basis for copy number analysis within the region by Southern blot and fluorescence in situ hybridization. Seven specific and independent amplification maxima were identified in breast cancer cell lines and breast tumors. We present correlative amplification and overexpression studies for the FLJ21316 and Hs.6649 genes suggesting a role for these candidates as amplification-dependent oncogenes.

Expression of an immediate early gene, IEX-1, in human tissues

IEX-1 is an immediate early gene that is induced by ionizing radiation, ultraviolet radiation, and a variety of growth factors. It plays an important role in the regulation of cellular growth. Earlier, we performed studies on the distribution of IEX-1 messenger RNA in different tissues and on the subcellular localization of IEX-1 protein. No reports, however, have appeared concerning the distribution of IEX-1 protein in a variety of human tissues. We raised a polyclonal antibody against a synthetic IEX-1 peptide (amino acids 51-75) and used the antibody to study the distribution of the protein in human tissues. We demonstrate that IEX-1 is strongly expressed in epithelia of the skin, trachea, gastrointestinal, and genitourinary systems, as well as in the pancreas and breast. Endothelial cells within the vasculature of most tissue/organs also strongly express IEX-1. Liver, lung, lymph nodes, and placenta stain weakly. No IEX-1 epitopes were detected in the thymus, testes, ovary, myocardium, skeletal muscle, or spleen. We conclude that IEX-1 is widely expressed in epithelial and endocrine tissues, as well as in vascular endothelium.

Transcriptional complementarity in breast cancer: application to detection of circulating tumor cells

BACKGROUND

We used a combination of genetic subtraction, silicon DNA microarray analysis, and quantitative PCR to identify tissue- and tumor-specific genes as diagnostic targets for breast cancer.

METHODS AND RESULTS

From a large number of candidate antigens, several specific subsets of genes were identified that showed concordant and complementary expression profiles. Whereas transcriptional profiling of mammaglobin resulted in the detection of 70% of tumors in a panel of 46 primary and metastatic breast cancers, the inclusion of three additional markers resulted in detection of all 46 specimens. Immunomagnetic epithelial cell enrichment of circulating tumor cells from the peripheral blood of patients with metastatic breast cancer, coupled with RT-PCR-based amplification of breast tumor-specific transcripts, resulted in the detection of anchorage-independent tumor cells in the majority of patients with breast cancer with known metastatic disease.

CONCLUSION

Complementation of mammaglobin with three additional genes in RT-PCR increases the detection of breast cancers in tissue and circulating tumor cells.

Discrepancies in Clinical Laboratory Testing of Eligibility for Trastuzumab Therapy: Apparent Immunohistochemical False-Positives Do Not Get the Message

BACKGROUND: Several studies have reported what seem to be false-positive results using the Food and Drug Administration (FDA)–approved HercepTest (Dako Corp, Carpinteria, CA) to profile Her-2/neu amplification and overproduction in breast carcinoma. False-positive status has been based on comparisons with gene copy enumeration by fluorescence in situ hybridization (FISH) and with comparisons to immunohistochemistry (IMH) results using a monoclonal antibody. However, simple overexpression by tumor cells that have normal gene copy has not been evaluated by profiling mRNA expression, ie, such cases could simply represent true-positive, transcriptionally upregulated overexpression.

MATERIALS AND METHODS: Four hundred infiltrating ductal carcinomas of breast were evaluated by IMH using monoclonal (CB11; Ventana Medical Systems, Inc, Tucson, AZ) and polyclonal (HercepTest; Dako) antibodies after antigen retrieval (AR). A polyclonal antibody sans AR (PCA/SAR) was also used. All IMH stains were evaluated and scored according to the guidelines for the FDA-approved HercepTest. A total of 145 of 400 carcinomas were subsequently evaluated by direct and digoxigenin-labeled (Dig) FISH, and 144 of 400 were evaluated by detection of mRNA overexpression via autoradiographic RNA:RNA in situ hybridization.

RESULTS: Overall HercepTest/CB11 IMH discordance was 12%. Expression of mRNA was highly concordant with FISH and DigFISH amplification and with CB11 and PCA/SAR immunohistology. IMH false-positive cases (no Her-2/neu gene amplification) occurred with both HercepTest (23%) and CB11 (17%), and the majority of false-positive results (34 of 44) were scored as 2+. All 2+ false-positive cases were mRNA-negative. Combined results of HercepTest and CB11 showed that 79% (38 of 48) of 3+ cases were Her-2/neu gene amplified, but only 17% (seven of 41) of 2+ cases had increased gene copy.

CONCLUSION: Discordant HercepTest/FISH results, and to a lesser extent discordance with CB11 IMH, are most commonly false-positive results with a score of 2+. The 2+ score as defined in the guidelines for the FDA-approved HercepTest should not be used as a criterion for trastuzumab therapy unless confirmed by FISH. Determination of Her-2 gene copy number by FISH may be a more accurate and reliable method for selecting patients eligible for trastuzumab therapy.

Loss of alternately spliced messenger RNA of the luteinizing hormone receptor and stability of the follicle-stimulating hormone receptor messenger RNA in granulosa cell tumors of the human ovary

OBJECTIVES

The expression of messenger RNA (mRNA) for the LH (LHR) and FSH receptors (FSHR) was examined in normal human corpora lutea and granulosa cell tumors.

METHODS

Expression was examined by RT/PCR and DNA sequencing techniques.

RESULTS

The full-length (FL) coding region and seven additional isoforms were identified for normal LHR mRNA. Isoform 1 had portions of exons II and III deleted, and isoform 2 had exon IX omitted. Isoform 3 also had portions of exons II and III deleted and all of exon IX deleted. Exons III through VI were missing in isoforms 4-7. Isoform 5 also had exon IX omitted, and isoform 6 also had part of exon XI missing. Isoform 7 also had exon IX and part of exon XI deleted. An aberrant migration pattern of the LHR mRNA isoforms was observed for granulosa cell tumors with FIGO Stage I-IV. Five tumor samples of Stage III-IV had many isoforms absent. Seven Stage I samples had aberrant migration patterns that depended on the size of the tumor. As the size of the tumor increased the aberrant migration pattern of the LHR mRNA isoforms was more pronounced and some isoforms were not detected. The FL and at least one additional isoform were identified for FSHR mRNA. Isoform 1 had regions of exons IV and V deleted. The FSHR mRNA isoforms had a similar migration pattern for the normal ovary and the granulosa cell tumors.

CONCLUSIONS

Alternately spliced forms of mRNA for the LHR and FSHR exist for normal human ovary and granulosa cell tumors. The aberrant migration and missing LHR mRNA isoforms in granulosa cell tumors do not appear to result from general genomic instability associated with tumor progression. These findings are important to understand the role of alternate splicing in the regulation of LHR and FSHR expression in different pathological states.

17q23 amplifications in breast cancer involve the PAT1, RAD51C, PS6K, and SIGma1B genes

Amplification of the 17q23 region occurs frequently in breast tumors. To characterize the structure of 17q23 amplicons and to identify oncogene targets associated with this alteration, we performed a copy number analysis of 87 17q23 localized expressed sequence tags in seven breast cancer cell lines. Three major regions of amplification were detected in the MCF7 and BT474 cell lines. Amplification of at least one of four known genes (PAT1, PS6K, RAD51C, and SIGMA1B) was detected in the cell lines and in 28% of 94 breast tumors. In most cases, these four genes were overexpressed when amplified, but there was a particularly good association between amplification of the SIGMA1B gene and elevated expression in tumors, which suggested a possible role for this gene in tumor progression. Our data show that this region contains at least four independent targets of amplification, which suggests that there is considerable variability in the structure of the 17q23 amplicon.

Prognostic value of bone marrow angiogenesis in multiple myeloma

We studied the prognostic value of angiogenesis grading and microvessel density estimation in newly diagnosed multiple myeloma. Seventy-five patients with newly diagnosed myeloma, treated on Eastern Cooperative Oncology Protocol E9486 and Intergroup study 0141 (S9321) at the Mayo Clinic, were studied. Bone marrow microvessels were examined using immunohistochemical staining for von Willebrand factor. Determination of microvessel density and angiogenesis grading was done in a blinded manner. There was a strong correlation between microvessel density and the plasma cell labeling index, rho 0.42, P < 0.001. Angiogenesis grade was also significantly associated with the plasma cell labeling index. Fifteen % of patients with low-grade angiogenesis had a high labeling index (>1%). In contrast, 47% of patients with intermediate or high-grade angiogenesis had high labeling indices (P = 0.02). Overall survival was significantly different among those with high-, intermediate-, and low-grade angiogenesis, with median times of 2, 4, and 4.4 years, respectively (P = 0.02). Similarly, patients with microvessel density >50/x400 field had poorer survival compared with those with 50 or fewer microvessels/field, median survival 2.6 versus 5.1 years, respectively (P = 0.004). There was a strong association between angiogenesis grade and microvessel density (P < 0.001). We conclude that bone marrow angiogenesis is a predictor of poor survival in newly diagnosed myeloma. Angiogenesis is correlated with the plasma cell labeling index but not the bone marrow plasma cell percentage. A simple visual grading of angiogenesis is an efficient alternative to microvessel density estimation.

Pretreatment assessment of prognostic indicators in endometrial cancer

OBJECTIVE

The object of this study was to assess the association of histologic, cytokinetic, and molecular variables in preoperative endometrial samples with extrauterine disease, recurrence, and survival among patients with endometrial cancer.

STUDY DESIGN

In a case-cohort study of 125 women, ploidy, S-phase fraction, proliferative index, deoxyribonucleic acid index, proliferating cell nuclear antigen, MIB-1 proliferation marker, p53 tumor suppressor gene, and cytoplasmic HER-2/neu oncogene and bcl-2 expressions were quantitated.

RESULTS

A model with only one independent term predicted progression-free survival; that variable was p53 (P <. 0001; relative risk, 5.60). A model with two independent terms predicted disease-related survival; these variables were p53 (P =. 0002; relative risk, 7.39) and MIB-1 (P =.03; relative risk, 3.27). Among patients with tumors with both p53 and MIB-1 expression exceeding 33%, a total of 32% had died of disease by 2 years. A model for predicting extrauterine disease selected two independent variables: p53 (odds ratio, 3.20; P =.01) and ploidy (odds ratio, 2. 16; P =.04). An advanced surgical stage was encountered in 26% to 35% of cases in which either the p53 expression exceeded 33% or the deoxyribonucleic acid content was nondiploid and in 53% of cases in which both variables were unfavorable.

CONCLUSIONS

Preoperative evaluation of quantifiable cytokinetic and molecular variables can assist in identifying tumor types that are predisposed toward a more aggressive clinical course.

Assessment of inhibin and p53 in granulosa cell tumors of the ovary

OBJECTIVE

The goal of this work was to determine the cellular content of inhibin and p53 in granulosa cell tumors (GCTs).

METHODS

Clinical records of 47 patients (mean age, 54 years; range, 20-85 years) presenting with GCT surgically managed at our institution were abstracted. International Federation of Gynecology stage I was assigned in 39 patients, stage II in 2, and stage III in 6. Concomitant endometrial carcinoma was identified in 6 patients. Mean follow-up was 13.6 years (range, 1 day to 37.6 years). Sections from paraffin-embedded tissue blocks were analyzed immunohistochemically for expression of tissue inhibin and p53 levels. Inhibin expression was graded by intensity and reactivity, and p53, by its presence or absence.

RESULTS

The tumors of 27 patients (57%) stained strongly for inhibin intensity and showed >60% reactivity. Decreased intensity and reactivity of inhibin expression were associated with advanced-stage disease (P = 0.05 and P < 0.01, respectively, by Fisher exact test). Expression of p53 was detected in tumors from 27 patients (57%), and immunoreactivity was associated with compromised progression-free survival (P = 0.016, log-rank test). However, the association between p53 immunoreactivity and disease stage was not significant. Absence of p53 expression was significantly associated with concurrent endometrial carcinoma (P = 0.022), suggesting more molecularly intact tumors that retain functional activity.

CONCLUSIONS

Although the majority of GCTs show strong expression of inhibin with regard to intensity and reactivity, weak expression is associated with advanced disease but not with decreased progression-free survival. By contrast, expression of p53 is not significantly associated with stage, but increased expression is associated with decreased disease-free survival. Absence of p53 expression appears to be associated with concurrent endometrial carcinoma.

Adenoma-specific alterations of protein kinase C isozyme expression in Apc(MIN) mice

Members of the protein kinase C (PKC) family appear to play important roles in colorectal carcinogenesis. To investigate the potential involvement of PKC isozymes in adenomatous transformation induced by inactivation of the adenomatous polyposis coli (APC) gene product, we examined protein levels and localizations of ten PKC isozymes by immunohistochemistry in normal and adenomatous ileal epithelium of ApcMIN mice. Compared with surrounding normal epithelium, adenomas showed dramatically reduced staining for PKCs a, beta1, and zeta, as well as dysplasia-specific punctate nuclear staining of PKC mu. We conclude that reduced protein expression of PKC alpha, beta1, and zeta, and nuclear localization of PKC mu are markers of, and are perhaps involved in, adenomatous transformation induced by APC inactivation in ApcMIN mice.

HMSH6 alterations in patients with microsatellite instability-low colorectal cancer

Two microsatellite instability (MSI) phenotypes have been described in colorectal cancer (CRC): MSI-H (instability at >30% of the loci examined) and MSI-L (MSI at 1-30% of the loci examined). The MSI-H phenotype, observed in both hereditary nonpolyposis colon cancer-associated CRC and approximately 15% of sporadic CRC, generally results from mutational or epigenetic inactivation of the DNA mismatch repair (MMR) genes hMSH2 or hMLH1. The genetic basis for the MSI-L phenotype, however, is unknown. Several other proteins, including hMSH3 and hMSH6, also participate in DNA MMR. Inactivating mutations of MSH6 in yeast and human tumor cell lines are associated with an impaired ability to repair single-base mispairs and small insertion-deletion loops but not large insertion-deletion loops. This suggests that hMSH6 mutations are more likely to be associated with a MSI-L phenotype than a MSI-H phenotype in CRC. To explore this possibility, we screened tumors from 41 patients with MSI-L CRC for hMSH6 mutations with conformation-sensitive gel electrophoresis (CSGE) and for hMSH6 protein expression by immunohistochemistry. Alterations found with CSGE were confirmed by DNA sequencing of normal and tumor tissue. One somatic (Asp389Asn) and 15 germ-line changes were found. Of the 15 germ-line changes, 9 were found in an intron (none involving splice junctions), and 6 were found in an exon (Gly39Glu, Leu395Val, and 4 silent alterations). Immunohistochemical staining for hMSH6 performed on 34 of the 41 tumors revealed strong nuclear hMSH6 expression in all of the cases. Overall, our results suggest that hMSH6 mutations do not play a major role in the development of sporadic CRC with a MSI-L phenotype.

Molecular and cytokinetic pretreatment risk assessment in endometrial carcinoma

OBJECTIVE

Our objective was to determine whether cytokinetic and molecular analyses of curettage specimens can provide a mechanism for triage of patients with endometrial cancer before initiating definitive surgical treatment.

METHODS

Pretreatment analysis consisted of flow cytometric determination of ploidy, S-phase fraction (SPF), and proliferative index (PI) and immunohistochemical determination of expression of proliferating cell nuclear antigen, HER-2/neu, and p53 in curettage specimens from 134 patients with endometrial carcinoma who subsequently had surgical staging and definitive surgical treatment. Fisher's exact test or chi(2) was used to examine the association between pretreatment variables and traditional surgical-pathologic indices. The log-rank test was used for univariate survival analysis. Cox proportional hazards identified the most important molecular factors.

RESULTS

Nondiploid status, SPF >/=9%, and PI >/=14% were associated with the traditional posttreatment prognostic indices, stage, grade, and histologic subtype. Univariate survival analysis demonstrated a correlation between nondiploid status, SPF >/=9%, PI >/=14%, and p53 overexpression and decreased progression-free survival (PFS) and disease-related survival (DRS). Stepwise Cox regression analysis identified p53 overexpression and SPF >/=9% as the most significant pretreatment molecular risk factors. A model stratifying patients according to whether none, one, or both of these two pretreatment factors were present showed that when both factors are present the risk for recurrence was higher (RR = 7.07; 95% confidence interval [CI], 3.06-16.38; P < 0.01) and death due to disease was higher (RR = 9.93; 95% CI, 3.92-25.19; P < 0.01) than when no factors are present. In the group with both factors, 5-year PFS and DRS estimates were 41 and 44%, respectively, compared with 86 and 86% and 90 and 92% for the "none" and "one" groups, respectively.

CONCLUSION

When observed simultaneously, increased SPF and p53 overexpression defined a group of patients at high risk for rapid recurrence and death due to disease. Pretreatment molecular analysis of curettage specimens could provide a mechanism of triage that could be applied before definitive surgical treatment.

Immunodiscrimination of colorectal neoplasia using MUC1 antibodies: discrepant findings in tissue versus stool

Colorectal tumor-associated antigens are attractive targets for novel stool-screening assays. MUC1, a glycoprotein antigen, is aberrantly expressed in transformed colorectal mucosa and represents a candidate fecal biomarker. In this study, tissue staining and stool testing were performed to further clarify the discriminant potential of MUC1 in markedly different biologic media. One anti-MUC1 monoclonal antibody (MA5) was used for immunohistochemistry and two commercially available MUC1 assay kits (ELSA-CA 15-3 and Truquant BR) were used for stool detection. On tissue staining, MUC1 expression was strong in 40/40 (100%) adenocarcinomas, moderate in 42/55 (76%) adenomas, faint in 8/28 (29%) juxtatumoral mucosa specimens, and absent in 15/15 (0%) nonadjacent mucosa specimens. Conversely MUC1 levels in stool testing did not differ between colorectal cancer cases (N = 14) and controls (N = 14). Based on these results, MUC1 appears to be a functional tumor biomarker in colorectal tissue but not in stool. Bacterial metabolism within stool may unmask the core antigen of MUC1 and account for this discordance in immunoreactivity.

Morphometric analysis of the "mucocellular layer" overlying colorectal cancer and normal mucosa: relevance to exfoliation and stool screening

Characterization of shed cell elements entrapped within the colorectal surface mucus would be valuable to the study of exfoliation and candidate stool screening markers. Yet, surprisingly little is known about the cellular composition of this "mucocellular layer" (MCL). Our aim was to describe and compare the histomorphometry of the MCL that overlies colorectal cancer (CRC) and normal mucosa. From tissue archives, 20 resected CRC specimens yielding perpendicular cuts of both tumor surface and adjacent normal mucosa were consecutively selected. MCL thickness and cell number were determined in triplicate using an ocular micrometer. Cellular elements within the MCL were characterized on paraffin sections by immunohistochemistry. Mean cell density was much greater in the MCL over CRC (2,639 +/- 2,178 per mm2) than over normal mucosa (184 +/- 395 per mm2), p < .001. Robust-appearing colonocytes and inflammatory cells predominated in the hypercellular MCL of CRC; the former retained expression of tumor-associated antigens. In contrast, the sparsely scattered cells within the normal MCL were typically apoptotic and of indeterminate lineage. Based on direct observations from this first descriptive study of the colorectal MCL, luminal shedding appears to be much greater from CRC than from normal mucosa.

Monoclonal antibodies against the human sodium iodide symporter: utility for immunocytochemistry of thyroid cancer

The recent cloning of the thyroidal protein that is responsible for iodide transport, the sodium iodide symporter (hNIS), has made possible studies designed to characterize its structure, function and expression in thyroidal tissues. Using a mannose binding protein (MBP)-hNIS fusion protein as antigen, we have developed mouse monoclonal antibodies against hNIS to utilize as tools in such studies. Twenty-four clones were initially recovered which recognized the MBP-hNIS fusion protein, but only two of them were specific for hNIS while the others recognized MBP alone. Both antibodies were found to be immunoglobulin G (IgG) 1kappa (kappa). The specificity of antibodies was tested by Western blotting using membranes prepared from COS-7 cells transiently transfected with the pcDNA3 plasmid containing the full-length hNIS cDNA, or cells transfected with the pcDNA3 vector. A major band with a molecular weight (MW) of approximately 97 kDa, and several minor bands with MW of approximately 160 kDa, approximately 68 kDa, approximately 30 kDa and approximately 15 kDa, were detected specifically in the hNIS-transfected cells. After enzymatic deglycosylation, the major band was present at 68 kDa, as expected based upon the amino acid sequence of hNIS. Immunohistochemistry was performed with several different types of thyroid tissue and non-thyroidal tissues, using the monoclonal antibodies. Strong immunostaining was observed in Graves' tissue, with intermediate staining in papillary and follicular thyroid cancers and an absence of staining in Hürthle cell cancer. The staining was specific for the follicular epithelium and was concentrated in the basolateral portion of the cell membrane. These monoclonal hNIS antibodies should prove useful in the characterization of NIS expression in benign and malignant thyroid tissue and in studies characterizing its structure and function.

p73 mutations are not detected in sporadic and hereditary breast cancer

Recently, a novel tumor suppressor gene, p73, was isolated and mapped to chromosome 1p36, a region commonly associated with loss of heterozygosity in neuroblastoma and other human malignancies, including breast cancer. The p73 gene shares considerable homology with the common tumor suppressor gene p53, both in composition and function. This study examines the potential participation of p73 in the pathogenesis of sporadic and hereditary breast cancers. Mutation analysis of 29 hereditary breast cancer cases revealed five independent silent mutations in the hereditary cases that are unlikely to play a role in tumor development. Mutation analysis of 48 sporadic breast tumors did not identify any unique variants. Eleven common polymorphisms scattered throughout the gene were also detected. Thus, mutations in the p73 gene appear to play little if any role in hereditary or sporadic breast cancer.

MAGE-1 and MAGE-3 tumor rejection antigens in human germ cell tumors

The MAGE-1 and MAGE-3 genes are members of the melanoma antigen-encoding gene family. These genes encode for HLA-restricted tumor-associated rejection antigens recognized by cytotoxic T lymphocytes. MAGE-1 and MAGE-3 gene expression has been identified in a number of human malignancies, and MAGE-1 and MAGE-3 antigenic peptides are potential targets for tumor-specific immunotherapy. The only normal tissues known to express these genes are testicular germ cells and placental tissue. The objective of this study was to examine MAGE-1 and MAGE-3 antigens immunohistochemically in testicular germ cell tumors, including seminoma, a germ cell tumor frequently associated with a lymphoid infiltrate. Forty-three germ cell tumors (24 seminomas, six embryonal carcinomas and 13 mixed germ cell tumors), and 10 Leydig cell tumors were selected for study, and standard immunohistochemical techniques were used on formalin-fixed paraffin-embedded tissues using mouse monoclonal antibodies to MAGE-1 (clone M454) and MAGE-3 (clone 57B) antigens. MAGE-1 antigen was identified in 16.6% of seminomas. No embryonal carcinomas, yolk sac tumors, or teratomas contained MAGE-1 protein. MAGE-3 antigen was identified in 41.8% of seminomas, and this protein was not identified in embryonal carcinomas, yolk sac tumors, or teratoma. Spermatogonia and primary spermatocytes contained MAGE-1 and MAGE-3 antigen, and more mature forms, including spermatids, were weakly positive to negative. Leydig cell tumors were negative for MAGE-1 and MAGE-3. In seminoma, the presence of MAGE-1 and MAGE-3 antigens did not correlate with tumor size, tumor stage, the presence of a lymphoid infiltrate, or patient outcome. The low frequency of MAGE-specific HLA alleles in the population, the loss of the HLA class I antigens in neoplastic germ cells, and the finding that the majority of seminomas and all non-seminomatous germ cell tumors lacked MAGE-1 and MAGE-3 antigenic peptides indicate that immunotherapy directed towards MAGE-1 and MAGE-3 antigen is not a likely treatment option for seminoma and nonseminomatous germ cell tumors. The significance of MAGE-1 and MAGE-3 proteins in normal spermatogonia and primary spermatocytes will require additional study.

Loss of immunoreactivity for human calmodulin-like protein is an early event in breast cancer development

Cell proliferation requires calmodulin, a protein that regulates calcium-dependent enzymes involved in signal transduction pathways in eukaryotic cells. Calmodulin-like protein (CLP) is found in certain epithelial cell types, including normal breast epithelium, and, although it closely resembles calmodulin in amino acid sequence, CLP interacts with different proteins than does calmodulin. The observation that CLP mRNA expression is dramatically reduced in transformed breast epithelial cells led to two hypotheses: (1) CLP helps to maintain the differentiated state in epithelial cells; and (2) downregulation of CLP accompanies malignant transformation of breast epithelial cells. The objective of this study was to determine if the expression of CLP in human breast cancer specimens is reduced in comparison to its expression in normal breast tissue. Eighty human breast cancer biopsy specimens were analyzed immunohistochemically for CLP expression by using a polyclonal rabbit antihuman CLP antibody. CLP expression was reduced in 79% to 88% of the invasive ductal carcinoma and lobular carcinoma specimens and in a similar fraction of the ductal carcinoma in-situ specimens, compared with normal breast specimens. None of the breast cancer specimens showed an increase in CLP expression. These findings support the hypotheses that CLP behaves as a functional tumor suppressor protein and is downregulated early in breast cancer progression.

Extension of useful reagent shelf life beyond manufacturers' recommendations. Cell Markers Committee of the College of American Pathologists

OBJECTIVE

The College of American Pathologists Cell Markers Committee designed a study to evaluate the use of immunohistochemistry primary antibodies beyond manufacturers' recommended dates.

METHODS

Pathologists were asked to save aliquots of primary antibodies during mid-1997 so that by spring 1998 the reagents would be "outdated" according to manufacturers' recommendations. Three tumors were immunostained both in mid-1997 and early 1998 (using outdated reagents in 1998). Two hundred twenty-one laboratories participated.

PATIENT SAMPLES

Immunostained materials consisted of an angiomyolipoma immunostained for muscle-specific actin and HMB-45, a melanoma immunostained for S100 protein and HMB-45, and a large cell lymphoma immunostained for common leukocyte antigen and HMB-45. Blocks from the same tumor were used in each instance.

MAIN OUTCOME MEASURE

We compared the immunostaining results as a percentage of laboratories indicating a positive or negative immunohistochemical result between the 1997 and 1998 time points.

RESULTS

Only minor differences were identified for the 221 reporting laboratories in 1998 as compared with those in 1997.

CONCLUSIONS

The data suggest review of the Health Care Financing Administration's ruling on extending the useful reagent shelf life beyond manufacturers recommendations. Similar studies using more inherently quantitative methodology are suggested.

Molecular markers in male breast carcinoma

BACKGROUND

In contrast to female breast carcinoma, information regarding the prevalence and prognostic information of new molecular markers is limited in male breast carcinoma. The objective of this study was to assess the degree of expression and prognostic value of estrogen receptors (ER), progesterone receptors (PR), androgen receptors (AR), bcl-2, p53, HER-2/neu, cyclin D1, and MIB-1 in a cohort of male breast carcinoma patients.

METHODS

A computerized search of the medical index, tumor registry, and tissue registry was used to identify 111 male patients with a diagnosis of primary adenocarcinoma of the breast seen between 1950-1992 at the Mayo Clinic. Of these, 77 patients had adequate tissue specimens available for the immunohistochemical analysis of the markers. Immunoperoxidase staining was performed by an automated avidin-biotin complex method. Progression free (PFS) and overall (OS) survival distributions were estimated using the Kaplan-Meier method. The log rank test was used to determine whether any patient characteristic, tumor feature, or molecular marker was associated significantly with PFS or OS.

RESULTS

The majority of tumor specimens were positive for ER (91%), PR (96%), AR (95%), and bcl-2 (94%). Fewer positive specimens were found for cyclin D1 (58%), MIB-1 (38%), HER-2/neu (29%), and p53 (21%). The 5-year PFS and 10-year OS for the entire patient cohort was estimated to be 66% (95% confidence interval [CI], 57-77%) and 38% (95% CI, 29-50%), respectively. PFS was decreased significantly for those patients with tumors staining positively for MIB-1 (P=0.012) or negatively for cyclin D1 (P=0.009). OS was not found to differ significantly with respect to these markers.

CONCLUSIONS

The nearly universal expression of hormone receptors in these tumors suggests a central role for endogenous hormones in male breast carcinoma. The high degree of AR expression would suggest that antiandrogen therapy should be explored further. The high frequency of bcl-2 positivity may implicate antiapoptotic mechanisms in the carcinogenesis of male breast carcinoma. The finding of decreased PFS in MIB-1 positive tumors supports the role of proliferative activity as a negative prognostic factor in male breast carcinoma. Positive cyclin D1 expression is associated with increased PFS in male breast carcinoma patients, which suggests that interactions among cell cycle regulatory proteins may be important in this disease.

Inhibin A is a sensitive and specific marker for testicular sex cord-stromal tumors

We compared the expression of inhibin A, chromogranin, synaptophysin, S-100 protein, cytokeratins AE1/AE3, 7, and 20, and estrogen and progesterone receptors in testicular sex cord-stromal tumors: 11 Sertoli cell tumors, 3 Sertoli cell adenomas (nodules), 26 benign Leydig cell tumors, 7 malignant Leydig cell tumors (defined clinically by metastatic behavior), and a variety of germ cell tumors. Inhibin was the most sensitive marker, expressed in 91% of the Sertoli cell tumors and 100% of the Sertoli cell adenomas and Leydig cell tumors. The non-neoplastic Sertoli and Leydig cells invariably stained for inhibin. Conversely, no germ cell tumors were immunoreactive. One testicular tumor of the adrenogenital syndrome was immunoreactive. Neuroendocrine marker immunoreactivity was variable. Chromogranin was expressed in the non-neoplastic Sertoli and Leydig cells, 82% of the Sertoli cell tumors, 92% of the benign Leydig cell tumors, and 43% of the malignant Leydig cell tumors. Synaptophysin was expressed in the non-neoplastic Sertoli and Leydig cells, 45% of the Sertoll cell tumors, and 70% of the Leydig cell tumors, in approximately similar proportions between the benign and malignant Leydig cell tumors. S-100 protein was expressed in 64% of the Sertoli cell tumors, 8% of the benign Leydig cell tumors, and none of the malignant Leydig cell tumors. Cytokeratins AE1/AE3 were expressed in 64% of the Sertoli cell tumors and 42% of the Leydig cell tumors, with similar proportions in the benign and malignant cases. Estrogen and progesterone receptor expression were identified in 24 and 39% of benign and malignant Leydig cell tumors, respectively. We conclude that inhibin is a characteristic marker for Sertoli and Leydig cells and that it serves to differentiate testicular sex cord-stromal tumors from germ cell tumors.

Hypermethylation of the hMLH1 promoter in colon cancer with microsatellite instability

Recent studies have demonstrated the presence of microsatellite instability (MSI) in tumors from patients with hereditary nonpolyposis colon cancer and in a subset of patients with sporadic colorectal cancer (CRC). In sporadic CRC, three tumor phenotypes have been defined: microsatellite stable (MSS), low-frequency MSI, and high-frequency MSI (MSI-H). Although defective mismatch repair, consisting primarily of alterations in hMSH2 and hMLH1, is believed to be responsible for the MSI phenotype in the majority of patients with hereditary nonpolyposis colon cancer, the genetic defect responsible for this phenotype in sporadic CRC has yet to be clearly delineated. Somatic or germ-line alterations in these two genes have been identified in only a minority of these cases. Analysis of the protein expression patterns of hMSH2 and hMLH1 in unselected CRC, however, suggests that alterations in hMLH1 may account for a majority of the MSI-H cases. In an effort to explore the underlying molecular basis for these findings, we have examined the methylation status of the presumptive hMLHI promoter region in 31 tumors that vary in regard to their MSI status (MSI-H or MSS), their hMLH1 protein expression (MLH- or MLH+), and their gene mutation (Mut+ or Mut-) status. Hypermethylation of the hMLH1 promoter occurred in all 13 MSI-H/ MLH- tumors that did not have a detectable mutation within the hMLH1 gene. Of those MSI-H tumors containing germ-line or somatic alterations in hMLH1 (n = 7, including 3 frameshift, 1 nonsense, 2 missense mutations, and 1 tumor containing multiple mutations: missense, splice-site alteration, and a frameshift), four had a normal methylation pattern, whereas three others demonstrated hypermethylation of the hMLH1 promoter region. Two of these cases had a missense alteration, the other a frameshift alteration. The single MSI-H/Mut+ tumor that had normal hMLH1 and hMSH2 expression, as well as 9 of the 10 MSS cases, lacked methylation of the hMLH1 promoter. Hypermethylation of the hMSH2 promoter was not observed for any of the cases. These results suggest that hypermethylation of the hMLH1 promoter may be the principal mechanism of gene inactivation in sporadic CRC characterized by widespread MSI.

The expression of Fas Ligand by macrophages and its upregulation by human immunodeficiency virus infection

Fas/Fas Ligand (FasL) interactions play a significant role in peripheral T lymphocyte homeostasis and in certain pathological states characterized by T cell depletion. In this study, we demonstrate that antigen-presenting cells such as monocyte-derived human macrophages (MDM) but not monocyte-derived dendritic cells express basal levels of FasL. HIV infection of MDM increases FasL protein expression independent of posttranslational mechanisms, thus highlighting the virus-induced transcriptional upregulation of FasL. The in vitro relevance of these observations is confirmed in human lymphoid tissue. FasL protein expression is constitutive and restricted to tissue macrophages and not dendritic cells. Moreover, a significant increase in macrophage-associated FasL is observed in lymphoid tissue from HIV (+) individuals (P < 0.001), which is further supported by increased levels of FasL mRNA using in situ hybridization. The degree of FasL protein expression in vivo correlates with the degree of tissue apoptosis (r = 0.761, P < 0. 001), which is significantly increased in tissue from HIV-infected patients (P < 0.001). These results identify human tissue macrophages as a relevant source for FasL expression in vitro and in vivo and highlight the potential role of FasL expression in the immunopathogenesis of HIV infection.

Microsatellite instability in colorectal cancer: different mutator phenotypes and the principal involvement of hMLH1

Recent studies have demonstrated the presence of microsatellite instability (MSI) in tumors from patients with hereditary nonpolyposis colorectal cancer and in a large number of sporadic tumors. To further characterize the type of alterations at these loci and their frequency of involvement in colon cancer, we studied DNA extracted from paraffin-embedded tissue from 508 patients using 11 microsatellites localized to chromosomes 5, 8, 15, 17, and 18. Overall, MSI at each locus varied in character and frequency and was observed with at least one marker in 191 cases (37.6%). Based on the number of markers displaying instability per tumor, three groups of patients were defined: those with <30% of the markers showing instability (MSI-L,, n = 109, 21.5%); those with > or = 30% (MSI-H, n = 82, 16.1%); and those showing no instability (MSS, n = 317, 62.4%). These groups were tested for correlations with a number of clinical and pathological parameters, including age, sex, stage, ploidy status, and site of tumor. Comparing across the three groups and verified by pair-wise comparisons, the MSI-H group was associated with tumor site (proximal colon, P = 0.001), sex (females, P = 0.005), stage (Dukes' B, P = 0.01), and ploidy status (diploid, P = 0.03). No significant differences were noted between the MSI-L and MSS group for any of the parameters tested. An additional 188 consecutive surgical colorectal cancer cases were examined for the presence of MSI and for the immunohistochemical expression of hMLH1 and hMSH2 proteins. Of this group, 129 (68.6%) were classified as MSS, 17 (9.0%) as MSI-L, and 42 (22.3%) as MSI-H. None of the MSS and none of the MSI-L tumors had altered expression of either hMLH1 or hMSH2. However, the majority of MSI-H (40 of 42, 95%) cases demonstrated absence of staining for these proteins. The most frequently altered protein was hMLH1, occurring in 95% of the tumors with altered expression. Cumulatively, these data suggest that the tumor phenotype MSI-H is distinct from tumor phenotypes MSI-L and MSS, with no apparent differences between MSI-L and MSS. Furthermore, altered hMLH1 protein expression appears to be responsible for the mutator phenotype in the vast majority of MSI-H tumors.

Placental site trophoblastic tumor: human placental lactogen and pregnancy-associated major basic protein as immunohistologic markers

Placental site trophoblastic tumor (PSTT) consists of a neoplastic proliferation of intermediate or extravillous trophoblast (also known as X cells). Pregnancy-associated major basic protein (pMBP) is a marker for placental intermediate trophoblast. We compared the distribution of pMBP and human placental lactogen (hPL) in 24 PSTT and 3 exaggerated placental site (EPS) specimens using two distinct immunohistologic methods. Statistical analyses were used to compare staining intensities in metastatic and nonmetastatic lesions. By immunofluorescence, 77% of the PSTT specimens and 100% of the EPS specimens stained with antibodies to pMBP, and the pMBP was localized in intermediate trophoblast and surrounding extracellular areas. By immunohistochemistry, 78% of the PSTT specimens and 100% of the EPS specimens stained for pMBP with a pattern comparable with that of immunofluorescence. Likewise, by immunohistochemistry, hPL stained 96% of the PSTT specimens and 100% of the EPS specimens. Immunohistochemical staining intensities for pMBP and hPL correlated (r2 = +.24; P = .013), but hPL staining was mainly confined to intermediate trophoblast and was more intense. Anti-pMBP tended to stain metastatic PSTT weakly. Thus, pMBP is a useful marker for intermediate trophoblast tumors and could help distinguish these from other forms of trophoblastic disease.

Overexpression of p34cdc2 protein kinase in epithelial ovarian carcinoma

OBJECTIVE

To investigate the role of expression of p34cdc2 protein kinase in normal, benign, and malignant ovarian epithelium.

MATERIAL AND METHODS

Tissue sections from 24 patients with epithelial ovarian carcinoma (EOC) along with 6 normal ovarian specimens and 12 benign cystadenomas were incubated with mouse IgG monoclonal antibody to human p34cdc2 protein kinase, followed by detection with use of a standard peroxidase-labeled streptavidin-biotin technique. Immunohistochemical staining was graded and compared. Clinical data were also reviewed.

RESULTS

Normal surface epithelium and 10 of 12 benign cystadenomas failed to stain for p34cdc2 protein kinase. Of the 24 EOC specimens, however, 19 (79%) stained positively. The staining pattern or intensity was not associated with the histologic grade or surgical stage.

CONCLUSION

Expression of p34cdc2 protein kinase is strongly up-regulated in most cases of EOC but not in normal epithelial ovarian tissue or in most cases of benign epithelial tumors evaluated. Therefore, it may be associated with early events in carcinogenesis. Redundant overexpression of cyclin-dependent kinases such as p34cdc2 may contribute to deranged cell cycle progression and proliferation of EOC. Observation of overexpression of p34cdc2 protein kinase in other malignant lesions suggests a common mechanism.

Expression of nm23/nucleoside diphosphate kinase-A protein in endometrial carcinoma

A metastatic tumor suppressor role for the nm23 gene product in breast carcinoma has been proposed. The biologic significance of nm23/NDP kinase-A (NDPK-A) expression in endometrial carcinoma remains undetermined. We sought to (1) characterize the pattern and intensity of nm23 protein expression in endometrial carcinoma and (2) assess the relationship between intensity/pattern of nm23 protein immunostaining and treatment response assessed by progression-free survival and survival to death. Formalin-fixed paraffin-embedded sections from 234 patients with endometrial cancer were immunostained with a mouse monoclonal IgG to nm23/NDPK-A protein. In most specimens of endometrial carcinoma (67.5%), nm23 expression was strongly upregulated. No association was found between either intensity (0 vs 1, 2, 3) or pattern (nuclear membrane vs cytoplasmic) of immunostaining and FIGO stage, ploidy status, histologic subtype, myometrial invasion, progression-free survival, or survival to death. Absence of nm23 staining (0 vs 1, 2, 3) was significantly associated with lower tumor grades (P = 0.02). For stage I patients, moderate to strong nm23 immunostaining intensity (2, 3) was associated with a trend toward diminished progression-free survival (P = 0.08). Our data imply a heterogeneity of nm23 protein expression and possible distinct biologic roles for nm23 in endometrial compared with breast or ovarian carcinoma.

Monoclonal antibodies specific for peptide epitopes of the epidermal growth factor receptor's extracellular domain

The ErbB tyrosine kinase receptor family plays an important role in normal cellular growth and differentiation. In addition, ErbB receptor family members are commonly amplified and overexpressed in various human neoplasms and tumor-derived cell lines, where it is believed that increased signalling as a result of receptor overexpression may play an important role in oncogenesis. Consequently, ErbB receptor family members are being investigated rigorously as potential biomarkers of cancer and as therapeutic targets in malignant tissues. Numerous studies now demonstrate the existence of "soluble" ErbB (sErbB) analogs in normal and cancerous tissues. These sErbB proteins embody the extracellular domain (ECD) of the receptor only; they are generated by either proteolytic cleavage or from truncated, alternatively spliced mRNA transcripts. Recently, we have identified an alternate transcript of the human c-erbB1 (Epidermal Growth Factor Receptor) proto-oncogene from placenta that encodes a sErbB1 protein of 60-kDa. This protein, p60 sErbB1, is glycosylated and secreted when expressed in transfected tissue culture cells in vitro. Although "soluble" receptor analogs may play important physiological roles in intercellular communication, tissue morphogenesis, tissue regeneration and repair, and embryogenesis by inhibiting or stimulating specific mitogenic and pattern forming signals, their mechanism of action has not been thoroughly elucidated. To further characterize sErbB1 expression in human tissues and cell lines and to better understand their role in carcinogenesis and normal development, we have generated monoclonal antibodies (MAbs) toward specific peptide epitopes of ErbB1 extracellular subdomains III and IV. These antibody reagents are described here and should be useful experimental, preparative, analytical, diagnostic, and therapeutic reagents for the study of sErbB1 molecules in normal development and cancer.

A functional determinant in human luteinizing hormone and chorionic gonadotropin: differential effect of mutations about beta-GLN-54

There is evidence that the conserved glutamine at residue 54 in the beta-subunit of human LH and and CG (hCG) is important for biological activity. Mutation to Arg in LH has been reported to impair receptor binding, leading to a documented case of hypogonadism, whereas in hCG the mutation has been shown to result in defective subunit association. Functional distinctions between LH and hCG have been described, but the significance of peptide-chain differences between the two has not been investigated systematically. We therefore compared the role of Gln-54 and its neighboring residues in both hormones, through replacement by amino acids with contrasting properties using site-directed mutagenesis. The mutant subunits were coexpressed with alpha-subunit in mammalian (Chinese hamster ovary) cells and the secreted hormones assayed for heterodimer formation, receptor binding, and steroidogenesis in murine Leydig cell tumor (MA-10) cells. Basic (Arg, Lys) substitution for Gln-54 in either hormone markedly impaired subunit association (<20% of wild-type) and the heterodimers that were formed were inactive (<5% of wild-type) in both assays. Arg-substituted hCG was also inactive in an adenylate cyclase assay using HEK-293 cells expressing rat LH/hCG receptor. After acidic (Glu) or neutral (Ala) substitution, heterodimer formation was less impaired (50-60% of wild-type), but effects on receptor interaction differed between the two hormones. The LH mutants still lacked binding activity, whereas the hCG products were fully active. The importance of residue 54 for receptor interaction appears to be sharply localized because mutation at adjacent positions (Pro-53 and Val-55) did not impair the activity of either hormone. Diminished heterodimer formation by Ile-53 mutation in LH (but not hCG), together with the similar effects of basic mutations at 54, imply long-distance effects as these residues are remote from alpha in the crystal structure. Our findings indicate that position 54 in LH and hCG is a determinant for both subunit association and receptor interaction. The differing responses between LH and hCG to certain mutations suggest that structural characteristics of the peptide chains may confer functional differences despite their close sequence homology.

Production of endothelium-derived factors from sodded expanded polytetrafluoroethylene grafts

PURPOSE

Experiments were designed to determine whether endothelium isolated from adipose tissue and sodded onto expanded polytetrafluoroethylene grafts release endothelium-derived vasoactive factors.

METHODS

Thin-walled expanded polytetrafluoroethylene grafts (6 mm internal diameter, 6 cm length, 30 microm pore size), one sodded with autogenous endothelial cells, the other unsodded, were implanted bilaterally in carotid arteries of 30 male mongrel dogs. Dogs were treated with 325 mg aspirin daily. After 6 weeks grafts were excised and perfused in a bioassay system. Effluent from the grafts stimulated with either acetylcholine, thrombin, adenosine 5-diphosphate, or the calcium ionophore A23187 was superfused over rings of canine femoral arteries without endothelium contracted with phenylephrine. Effluent from the grafts was analyzed by radioimmunoassay for thromboxane B2, 6-keto-prostaglandin F1alpha, endothelin-1, and C-type natriuretic peptide.

RESULTS

Ninety percent of the sodded grafts and 87% of the unsodded grafts were patent after 6 weeks. Bioassay rings superfused with effluent from sodded grafts stimulated with acetylcholine relaxed significantly more than rings superfused with effluent from similarly stimulated unsodded grafts. Biochemical analysis of the effluent showed an increase in 6-keto prostaglandin F1alpha and C-type natriuretic peptide and a decrease in endothelin-1 and thromboxane B2 release from the sodded compared with the unsodded grafts. Scanning electron microscopy showed a continuous layer of endothelial cells lining only the sodded grafts. Staining for alpha-actin and heavy-chain myosin showed a differentiated layer of smooth muscle below the endothelial layer on the sodded grafts. Finally, there was positive staining for C-type natriuretic peptide and endothelin-1 in the endothelium of the sodded grafts.

CONCLUSIONS

These results indicate that endothelial cells of sodded expanded polytetrafluoroethylene grafts produce endothelium-derived vasoactive factors. In addition, receptor-coupled synthesis/release of these factors is retained in sodded endothelial cells.

Absence of mutations in DNA mismatch repair genes in sporadic endometrial tumors with microsatellite instability

DNA mismatch repair genes have been reported to play a role in the pathogenesis of hereditary nonpolyposis colorectal cancer (HNPCC). Mutations of DNA mismatch repair genes have accounted for 90% of HNPCC-related colon and endometrial tumors. These mutations have been associated with microsatellite instability (MIN). Because endometrial cancer (EC) is the most common extracolonic malignancy associated with HNPCC, we hypothesized that similar molecular alterations may occur in sporadic endometrial tumors exhibiting MIN. Mutational analysis of the MSH2 and MLH1 genes was undertaken in sporadic EC that demonstrate MIN to determine the role of these genes in the pathogenesis of sporadic ECs. Established microsatellite markers were used to determine the incidence of MIN from 28 patients with sporadic EC. MIN was observed in 32% (9 of 28) of the tumor specimens analyzed. Mutational analysis of MSH2 and MLH1 genes was performed by immunohistochemical analysis and direct sequencing of tumor specimens that exhibited MIN. All 28 tumor specimens exhibited strong nuclear staining with both MSH2 and MLH1 antibodies, suggesting the absence of mutations. Sequencing of all exons of both the MSH2 and MLH1 genes in the nine MIN-positive tumor specimens demonstrated no mutations. We conclude that the MSH2 and MLH1 genes do not play a role in the pathogenesis of sporadic endometrial cancer.

Altered expression of hMSH2 and hMLH1 in tumors with microsatellite instability and genetic alterations in mismatch repair genes

To date, at least four genes involved in DNA mismatch repair (MMR) have been demonstrated to be altered in the germline of patients with hereditary nonpolyposis colon cancer: hMSH2, hMLH1, hPMS1, and hPMS2. Additionally, loss of MMR function has been demonstrated to lead to the phenomenon of microsatellite instability (MIN) in tumors from these patients. In this study, we have examined the protein expression pattern of hMSH2 and hMLH1 by immunohistochemistry in paraffin-embedded tumors from 7 patients with MIN+ sporadic cancer, 13 patients with familial colorectal cancer, and 12 patients meeting the strict Amsterdam criteria for hereditary nonpolyposis colon cancer. The relationship between the expression of these two gene products, the presence of germline or somatic mutations, and the presence of tumor MIN was examined. Nineteen of the 28 tumors studied demonstrated MIN, whereas mutations in hMLH1 and hMSH2 were detected in 6 and 2 patients, respectively. Of the eight MIN+/mutation+ cases, the absence of protein expression was observed for the corresponding gene product in all but one case (missense mutation in hMLH1). However, seven MIN+/mutation- cases also showed no expression of either hMLH1 (n = 5), hMSH2 (n = 1), or both (n = 1), whereas four MIN+/mutation- cases demonstrated normal expression for both. None of the MIN-/mutation- cases (n = 9) demonstrated an altered expression pattern for either protein. These data suggest that examination of protein expression by immunohistochemistry may be a rapid method for prescreening tumors for mutations in the MMR genes.

p53 expression in neurofibroma and malignant peripheral nerve sheath tumor. An immunohistochemical study of sporadic and NF1-associated tumors

Malignant peripheral nerve sheath tumors (MPNST) are highly malignant sarcomas arising either de novo or in transition from neurofibroma. Although relatively little is known of the molecular genetic alterations that underlie their formation, recent DNA sequencing studies have demonstrated the presence of p53 mutations in some MPNST. This tumor-suppressor gene has been implicated in the progression of a variety of human malignancies, including sarcomas. Employing the anti-p53 monoclonal antibody Do-7, this retrospective immunohistochemical study of p53 gene overexpression in MPNST found reactivity to be present in 68% and to be significant in degree in 57%. In contrast, although some degree of p53 overexpression was present in 48% of neurofibromas, none stained strongly and only 1 of the 27 (4%), a cellular example, showed significant staining. No difference in the frequency or degree of p53 staining was noted between MPNSTs from patients with or without neurofibromatosis 1. The observed overexpression of the gene product, possibly the reflection of a p53 gene mutation, suggests a role for p53 in the progression of neurofibroma to MPNST. Although the prognostic of p53 overexpression in MPNST remains to be confirmed, in the present series immunopositive tumors were associated with a shorter median patient survival (18 months) than were tumors showing no reactivity (82 months) (P = .02).

Prognostic value of p53 and proliferating cell nuclear antigen expression in endometrial carcinoma

The degree of expression of p53 and proliferating cell nuclear antigen (PCNA) was measured in archival samples from 221 patients managed surgically for endometrial carcinoma between 1979 and 1983. With use of primary antibodies to the p53 protein (DO7) and PCNA (PC10), immunoperoxidase nuclear staining of paraffin-embedded tissue was performed. The computerized CAS200 Image Analysis System was used to determine the percentage of nuclear area stained. There was no evidence to conclude that progression-free survival differed with respect to PCNA expression. In contrast, intense p53 expression (66% or more nuclear area stained) was significantly associated with compromised progression-free survival both in the analysis of all stages (P < 0.001) and in the subset of patients with stage I disease (P < 0.001). Intense expression of p53 was significantly associated with other prognostic indicators, including stage, grade, depth of myometrial invasion, histologic subtype, cytologic findings, DNA ploidy, and HER-2/neu expression. Multivariate analysis identified four independent prognostic factors for progression-free survival in endometrial carcinoma: intense p53 expression, histologic subtype, DNA ploidy status, and HER-2/neu expression. When none of these four independent factors are present, the 4-year progression-free survival is 96%. In contrast, it is 63% when one or more of these factors are present (P < 0.001) and 40% when two or more factors are present (P < 0.001).

Spontaneous diabetes mellitus in transgenic mice expressing human islet amyloid polypeptide

The islet in non-insulin-dependent diabetes mellitus (NIDDM) is characterized by loss of beta cells and large local deposits of amyloid derived from the 37-amino acid protein, islet amyloid polypeptide (IAPP). We have hypothesized that IAPP amyloid forms intracellularly causing beta-cell destruction under conditions of high rates of expression. To test this we developed a homozygous transgenic mouse model with high rates of expression of human IAPP. Male transgenic mice spontaneously developed diabetes mellitus by 8 weeks of age, which was associated with selective beta-cell death and impaired insulin secretion. Small intra- and extracellular amorphous IAPP aggregates were present in islets of transgenic mice during the development of diabetes mellitus. However, IAPP derived amyloid deposits were found in only a minority of islets at approximately 20 weeks of age, notably after development of diabetes mellitus in male transgenic mice. Approximately 20% of female transgenic mice spontaneously developed diabetes mellitus at 30+ weeks of age, when beta-cell degeneration and both amorphous and amyloid deposits of IAPP were present. We conclude that overexpression of human IAPP causes beta-cell death, impaired insulin secretion, and diabetes mellitus. Large deposits of IAPP derived amyloid do not appear to be important in this cytotoxicity, but early, small amorphous intra- and extracellular aggregates of human IAPP were consistently present at the time of beta-cell death and therefore may be the most cytotoxic form of IAPP.

Elevated nm23 protein expression is correlated with diminished progression-free survival in patients with epithelial ovarian carcinoma

OBJECTIVES

The role of the candidate metastasis-suppressor gene nm23-H1 first characterized in breast cancer remains controversial, with both metastasis suppression and disease progression being linked to elevated nm23-H1 gene expression in different human tumor types. We sought to characterize (1) the pattern and intensity of nm23-H1/nucleoside diphosphate (NDP) kinase expression in human epithelial ovarian carcinoma (EOC) and (2) the relationship between nm23-H1/NDP kinase expression and tumor extent at diagnosis (FIGO stage) and response to treatment as defined by progression-free survival and actuarial survival.

METHODS

Twenty-four patients with EOC aged 61.1 +/- 13.0 (mean +/- SD) years were followed for 614.0 +/- 289.7 days after a debulking procedure, cisplatin-based chemotherapy (19 of 24), and second-look laparotomy (9 of 24). After the primary debulking procedure, 63% of patients had no or microscopic residual disease. Overnight incubation of formalin-fixed tumor sections at 4 degree C with primary rabbit polyclonal IgG antibody to human nm23-H1/NDP kinase was followed by detection with standard ABC method. Nonimmune rabbit serum and normal breast tissue served as controls. Immunohistochemical staining was graded by a clinically blinded observer for intensity of staining (0, negative; 1, weak; 3, strong), pattern of staining (focal or diffuse), and histologic grade of tumor (1 through 4).

RESULTS

Of the EOCs, 54% were histologic grade 3 or 4 and 58% were FIGO stage III; 88% (21 of 24) stained positively, and 18 of 21 stained strongly and 14 of 21 stained diffusely. No correlation was found between either intensity or pattern of nm23-H1/NDP kinase immunostaining and histologic grade. No correlation was found between either staining pattern or intensity and FIGO stage. There was a trend toward decreased actuarial survival with both focal pattern (P = 0.12, log-rank test) and strong intensity (P = 0.15, log-rank test) of nm23-H1 staining. Decreased progression-free survival was likewise correlated with focal nm23-H1/NDP kinase immunostaining pattern (P = 0.02, log-rank test) and strong intensity of nm23-H1/NDP kinase staining (P = 0.08, log-rank test).

CONCLUSIONS

Expression of nm23-H1/NDP kinase is strongly upregulated in most EOCs. Redundant overexpression of nm23-H1/NDP kinase may contribute to deranged cell cycle progression and EOC proliferation. Pattern and intensity of nm23-H1/NDP kinase immunostaining of EOC tissue retrieved at primary operation may identify patients at risk for tumor progression and help guide treatment strategies. These findings suggest that nm23-H1 gene expression may have distinct if not opposite biologic functions in EOC and breast carcinoma.

Diabetes mellitus in cystic fibrosis is characterized by islet amyloidosis

A high proportion of patients with cystic fibrosis (CF) develop diabetes mellitus. In common with type II diabetes mellitus, diabetes mellitus in CF is characterized by a progressive decline in beta-cell function and an approximately 50% decline in beta-cell mass. It is not known whether islet amyloidosis (characteristic of type II diabetes mellitus) is present in diabetes mellitus complicating CF. To address this, pancreatic samples were obtained at autopsy from 9 control cases (without CF) and 41 cases of CF that were, in turn, subdivided into 13 nondiabetic, 12 borderline diabetic, and 16 diabetic cases based on clinical criteria. Islet amyloid was detected by light microscopy in 69% cases of CF with diabetes mellitus, 17% of cases with borderline diabetes mellitus, and none of the nondiabetic cases. Islet amyloid was not present in any of the control cases. Islet amyloidosis derived from islet amyloid polypeptide is a characteristic feature of diabetes mellitus in CF as well as type II diabetes mellitus.

Immunohistochemical detection and distribution of the 1,25-dihydroxyvitamin D3 receptor in rat reproductive tissues

Vitamin D3, via its active metabolite 1,25-dihydroxyvitamin D3, plays a critical part in male and female reproduction in the rat. 1,25-Dihydroxyvitamin D3 activity is mediated by an intracellular receptor (VDR). VDR distribution in reproductive tissue has not been studied using antibodies against the receptor. We developed a polyclonal antibody against the VDR and used it to examine VDR distribution in male and female rat reproductive tissues. In rat testes, VDR epitopes were observed in seminiferous tubules, specifically in spermatogonia, Sertoli cells and spermatocytes. Spermatozoa stained faintly. Epithelial cells of the epididymis, seminal vesicles and prostate also expressed VDR epitopes. In the female rat reproductive tract, immunostaining for VDR was seen in ovarian follicles, specifically in granulosa cells. Weaker VDR immunostaining was observed in follicular thecal cells and in the ovarian stroma and germinal epithelium. Corpus luteal cells stained intensely for VDR. Epithelium of fallopian tubes and the uterus also contained VDR epitopes. Both nuclear and cytoplasmic VDR immunostaining was observed in male and female rat reproductive tissues. We conclude that the VDR is widely distributed in male and female reproductive tissues and that it is likely to mediate actions of 1,25-dihydroxyvitamin D3 in the tissues.

Ontogeny of the 1,25-dihydroxyvitamin D3 receptor in fetal rat bone

To gain insights into 1,25-dihydroxyvitamin D3 receptor (VDR) function during fetal bone development, we examined fetal rat tissues from gestational days 13-21 for the presence and distribution of VDR using immunohistochemistry. Prior to ossification, VDR epitopes were observed in the mesenchyme condensing to form skeletal tissues, on day 13 in the developing vertebral column and limbs, and on day 17 of gestation in developing calvaria. Immunostaining for VDR was seen in proliferating and hypertrophic chondrocytes and in osteoblasts of limb buds and the vertebral column by day 17 of gestation. In calvaria, VDR epitopes were observed in osteoblasts by gestational day 19. VDR immunostaining was also evident in the skin of fetal limbs at all gestational ages examined. We show for the first time that the VDR appears very early in the developing fetal rat skeleton, suggesting that the VDR, in concert with its ligand, 1,25-dihydroxyvitamin D3, may play a role in the differentiation of mesenchymal precursors into bone tissue.

Aromatase expression in human germinomas with possible biological effects

Gonadal aromatase expression has been demonstrated in human Leydig, granulosa, and thecal cells, but never in human germ cells. In an attempt to explain the unique occurrence of isosexual precocious puberty in a young girl with a hCG-secreting suprasellar germinoma, we demonstrated the presence of aromatase expression in the germ cell component of this tumor. Immunohistochemical staining for P450-aromatase and hCG using a peroxidase-labeled streptaviden-biotin technique was performed on tumor specimens from the above patient and from four other subjects with central nervous system germinoma. Cytoplasmic aromatase staining was present in the germinoma cells of four of five cases of central nervous system germinoma studied. Staining was absent in the lymphocytic element within the tumor and in negative control tissues. The demonstration of aromatase activity in the malignant element of human germinomas indicates that aromatase expression can occur in human germ cells after malignant transformation. This parallels the finding that the transformation of Sertoli cells to sex cord tumor with annular tubules in Peutz Jeghers syndrome is associated with the induction of marked aromatase expression and systemic estrogen effect. We propose that tumor aromatase played a similar role in the unique occurrence of isosexual precocity in a girl with a suprasellar germinoma.

1 alpha, 25-dihydroxyvitamin D3 receptor ontogenesis in fetal renal development

We used immunohistochemical techniques to examine the distribution of 1 alpha, 25-dihydroxyvitamin D3 receptors (VDR) in developing rat and mouse kidneys and murine metanephric organ culture. In vivo, the patterns of expression in the two species were similar despite the slight difference in gestational periods (rat, 22 days; mouse, 19 days). Starting at gestational day 15, epitopes for VDR were found in cells of branching ureteral buds and in surrounding mesenchyme and at later developmental stages in glomerular visceral and parietal epithelial cells and proximal and distal tubules (DT). Epitopes for the 28-kDa calcium-binding protein (calbindin D28k) were found exclusively in DTs starting at gestational day 19. The pattern of VDR expression during in vitro nephrogenesis in serum-free murine metanephric organ culture paralleled that seen in vivo. At the time of explantation into organ culture (gestational day 13), VDR epitopes were not detected. By 3 days of in vitro development, VDR expression was identical to that found in gestational day 15 metanephroi in vivo. VDR expression after 5 days of in vitro development mirrored the pattern of gestational day 17 metanephroi in vivo. No calbindin D28k epitopes were seen at any in vitro developmental stage studied. We demonstrate for the first time that VDR are present in specific areas of the developing rat and mouse kidney early in gestation. Calbindin D28k appears later in developing rat and mouse kidney and is distributed differently than the VDR. Metanephric organ culture may be a useful model for studying the regulation and function of VDR during early renal development.

Acoustic schwannoma and pregnancy: a DNA flow cytometric, steroid hormone receptor, and proliferation marker study

For a long time, it has been speculated that pregnancy stimulates the growth of acoustic schwannomas. To test this hypothesis, immunohistochemical stains for estrogen receptor, progesterone receptor, and proliferating cell nuclear antigen (PCNA) were performed. Flow cytometric studies for DNA ploidy and S-phase fraction determinations were also performed. The study subjects included 6 female patients with unilateral acoustic tumors; at the time of tumor removal, 1 woman was pregnant and the other 5 women were 2 to 10 months postpartum. The age-sex-matched control group consisted of 6 men and 12 nonpregnant women, all with acoustic schwannomas similar in size to those of the study group. The study found no statistically significant association between the presence or quantity of estrogen or progesterone receptors and pregnancy, DNA ploidy, proliferation indices, or clinical data. Based on PCNA indices, large tumors tended to be less "biologically active" than small lesions (P < .01). The authors concluded that pregnancy does not significantly stimulate the cellular growth of acoustic schwannomas.