Skipping of FCER1G Exon 2 Is Common in Human Brain But Not Associated with the Alzheimer's Disease Genetic Risk Factor rs2070902

Background

Understanding the mechanisms whereby genetic variants influence the risk of Alzheimer's disease (AD) may provide insights into treatments that could reduce AD risk.

Objective

Here, we sought to test the hypothesis that a single nucleotide polymorphism (SNP) associated with AD risk, rs2070902, influences splicing of FCER1G exon 2.

Methods

AD and non-AD brain samples were analyzed for FCER1G expression by genotyping, immunohistochemistry, immunofluorescence, and qPCR.

Results

The protein encoded by FCER1G, FcRγ, is robustly expressed in microglia in both AD and non-AD brain. The FCER1G isoform lacking exon 2 (D2-FCER1G) was readily detectable. Moreover, the proportion of FCER1G expressed as this isoform was increased in brains with high AD neuropathology. However, the proportion of FCER1G expressed as the D2-FCER1G isoform was not associated with rs2070902 genotype.

Conclusions

In summary, the proportion of FCER1G expressed as the D2-FCER1G isoform is increased with AD neuropathology but is not associated with rs2070902.

Identification and Quantitation of Novel ABI3 Isoforms Relative to Alzheimer’s Disease Genetics and Neuropathology

Elucidating the actions of genetic polymorphisms associated with the risk of Alzheimer’s disease (AD) may provide novel insights into underlying mechanisms. Two polymorphisms have implicated ABI3 as a modulator of AD risk. Here, we sought to identify ABI3 isoforms expressed in human AD and non-AD brain, quantify the more abundant isoforms as a function of AD genetics and neuropathology, and provide an initial in vitro characterization of the proteins produced by these novel isoforms. We report that ABI3 expression is increased with AD neuropathology but not associated with AD genetics. Single-cell RNAseq of APP/PS1 mice showed that Abi3 is primarily expressed by microglia, including disease-associated microglia. In human brain, several novel ABI3 isoforms were identified, including isoforms with partial or complete loss of exon 6. Expression of these isoforms correlated tightly with total ABI3 expression but were not influenced by AD genetics. Lastly, we performed an initial characterization of these isoforms in transfected cells and found that, while full-length ABI3 was expressed in a dispersed punctate fashion within the cytosol, isoforms lacking most or all of exon six tended to form extensive protein aggregates. In summary, ABI3 expression is restricted to microglia, is increased with Alzheimer’s neuropathology, and includes several isoforms that display a variable tendency to aggregate when expressed in vitro.

An Alternatively Spliced TREM2 Isoform Lacking the Ligand Binding Domain is Expressed in Human Brain

Background: Genetic variants in TREM2 are strongly associated with Alzheimer’s disease (AD) risk but alternative splicing in TREM2 transcripts has not been comprehensively described. Objective: Recognizing that alternative splice variants can result in reduced gene expression and/or altered function, we sought to fully characterize splice variation in TREM2. Methods: Human blood and anterior cingulate autopsy tissue from 61 donors were used for end-point and quantitative PCR and western blotting to identify and quantify novel TREM2 isoforms. Results: In addition to previously described transcripts lacking exon 3 or exon 4, or retaining part of intron 3, we identified novel isoforms lacking exon 2, along with isoforms lacking multiple exons. Isoforms lacking exon 2 were predominant at approximately 10% of TREM2 mRNA in the brain. Expression of TREM2 and frequency of exon 2 skipping did not differ between AD samples and non-AD controls (p = 0.1268 and p = 0.4909, respectively). Further, these novel splice isoforms were also observed across multiple tissues with similar frequency (range 5.3 –13.0% ). We found that the exon 2 skipped isoform D2-TREM2 is translated to protein and localizes similarly to full-length TREM2 protein, that both proteins are primarily retained in the Golgi complex, and that D2-TREM2 is expressed in AD and non-AD brain. Conclusion: Since the TREM2 ligand binding domain is encoded by exon 2, and skipping this exon retains reading frame while conserving localization, we hypothesize that D2-TREM2 acts as an inhibitor of TREM2 and targeting TREM2 splicing may be a novel therapeutic pathway for AD.

Analysis of Genetic Variants Associated with Levels of Immune Modulating Proteins for Impact on Alzheimer's Disease Risk Reveal a Potential Role for SIGLEC14

Genome-wide association studies (GWAS) have identified immune-related genes as risk factors for Alzheimer’s disease (AD), including TREM2 and CD33, frequently passing a stringent false-discovery rate. These genes either encode or signal through immunomodulatory tyrosine-phosphorylated inhibitory motifs (ITIMs) or activation motifs (ITAMs) and govern processes critical to AD pathology, such as inflammation and amyloid phagocytosis. To investigate whether additional ITIM and ITAM-containing family members may contribute to AD risk and be overlooked due to the stringent multiple testing in GWAS, we combined protein quantitative trait loci (pQTL) data from a recent plasma proteomics study with AD associations in a recent GWAS. We found that pQTLs for genes encoding ITIM/ITAM family members were more frequently associated with AD than those for non-ITIM/ITAM genes. Further testing of one family member, SIGLEC14 which encodes an ITAM, uncovered substantial copy number variations, identified an SNP as a proxy for gene deletion, and found that gene expression correlates significantly with gene deletion. We also found that SIGLEC14 deletion increases the expression of SIGLEC5, an ITIM. We conclude that many genes in this ITIM/ITAM family likely impact AD risk, and that complex genetics including copy number variation, opposing function of encoded proteins, and coupled gene expression may mask these AD risk associations at the genome-wide level.

Reactivities of an anti-CEA peptide monoclonal antibody

Synthetic peptides representing different areas of the CEA molecule were used as immunogens for the development of anti-CEA antibodies. Both polyclonal and monoclonal antibodies were generated using peptides composed of CEA amino acid positions 99–128 and 585–613, respectively. One MAb, designated CP4, generated using the CEA peptide 99–128, was chosen for a more detailed analysis of reactivity. MAb CP4 reacts in solid phase RIAs with CEA peptide 99–128 immunogen and purified native CEA. CP4 did not react with purified non- specific cross reacting antigen (NCA), even though there were two single amino acid differences between NCA and CEA in the 29 amino acid peptide. The affinity constants of CP4 for the CEA peptide 99–128 and native CEA are 4.07 × 109M−1and 5.75 × 108M−1, respectively. When CP4 was reacted with purified CEA in Western blotting experiments, the Mr 180,000 glycoprotein characteristic of CEA was detected, but CP4 reacted to various size entities in tumor cell extracts. The results of liquid competition RIAs showed that the epitope that MAb CP4 recognized on native CEA is not available for binding when CEA is in solution. Physical (adsorption to a solid matrix) or chemical (deglycosylation or formalin-fixation) alteration of CEA is required for binding of CP4 to CEA. MAb CP4 reacted approximately 1,000-fold greater to deglycosylated CEA than native CEA. Immunohistochemical studies using formalin-fixed paraffin-embedded tissue sections demonstrated that, among carcinomas, CP4 reacts selectively with colorectal carcinomas, while normal colon is negative. Although stomach carcinoma is negative, dysplastic lesions and areas of intestinal metaplasia are reactive. Two of 7 normal stomach tissues showed focal cytoplasmic reactivity of the surface epithelium. CP4, therefore, appears to react with an epitope with highly restricted expression in colorectal carcinoma. These studies demonstrate the complexities in dealing with an anti-peptide MAb with reactivity to an epitope which is accessible only under certain conditions.

Alzheimer's Disease Genetics and ABCA7 Splicing

Both common and rare polymorphisms within ABCA7 have been associated with Alzheimer's disease (AD). In particular, the rare AD associated polymorphism rs200538373 was associated with altered ABCA7 exon 41 splicing and an AD risk odds ratio of ∼1.9. To probe the role of this polymorphism in ABCA7 splicing, we used minigene studies and qPCR of human brain RNA. We report aberrant ABCA7 exon 41 splicing in the brain of a carrier of the rs200538373 minor C allele. Moreover, minigene studies show that rs200538373 acts as a robust functional variant in vitro. Lastly, although the ABCA7 isoform with an extended exon 41 is predicted to undergo nonsense mediated RNA decay, this was not supported by qPCR analyses, which showed relatively normal ABCA7 mRNA levels in the carrier of the rs200538373 minor C allele. In summary, rs200538373 is a functional polymorphism that alters ABCA7 exon 41 splicing without grossly altering the level of ABCA7 mRNA.

Genetics of clusterin isoform expression and Alzheimer's disease risk

The minor allele of rs11136000 within CLU is strongly associated with reduced Alzheimer's disease (AD) risk. The mechanism underlying this association is unclear. Here, we report that CLU1 and CLU2 are the two primary CLU isoforms in human brain; CLU1 and CLU2 share exons 2-9 but differ in exon 1 and proximal promoters. The expression of both CLU1 and CLU2 was increased in individuals with significant AD neuropathology. However, only CLU1 was associated with the rs11136000 genotype, with the minor "protective" rs11136000T allele being associated with increased CLU1 expression. Since CLU1 and CLU2 are predicted to encode intracellular and secreted proteins, respectively, we compared their expression; for both CLU1 and CLU2 transfected cells, clusterin is present in the secretory pathway, accumulates in the extracellular media, and is similar in size to clusterin in human brain. Overall, we interpret these results as indicating that the AD-protective minor rs11136000T allele is associated with increased CLU1 expression. Since CLU1 and CLU2 appear to produce similar proteins and are increased in AD, the AD-protection afforded by the rs11136000T allele may reflect increased soluble clusterin throughout life.

Expression and regulation of a low-density lipoprotein receptor exon 12 splice variant

As low-density lipoprotein receptor (LDLR) contributes to cholesterol and amyloid beta homeostasis, insights into LDLR regulation may facilitate our understanding of cardiovascular disease and Alzheimer's disease. Previously, we identified LDLR isoforms that lacked exon 12 or exons 11-12 and that are predicted to encode soluble, dominant negative, LDLR. Moreover, these isoforms were associated with rs688, an exon 12 polymorphism that was associated with LDL-cholesterol and Alzheimer's disease risk. In this study, we present evidence that although the truncated LDLR isoforms are translated in vitro, they represent < 0.1% of CSF proteins. As these LDLR isoforms likely represent a loss of mRNA-encoding functional LDLR, we then focused upon identifying intron-exon boundary and exonic splicing enhancer elements critical to splicing. Exon 12 inclusion is enhanced by altering the 5' splice site in intron 12 towards a consensus splice donor sequence, consistent with its being a weak 5' splice site. Additionally, of the nine evolutionarily conserved putative splicing enhancer regions within exon 12, two regions that flank rs688 were critical to exon 12 inclusion. Overall, these results suggest that LDLR splice variants represent a loss of mRNA encoding functional LDLR and provide insights into the regulatory elements critical for LDLR exon 12 splicing.

Expression of SORL1 and a novel SORL1 splice variant in normal and Alzheimers disease brain

Background

Variations in sortilin-related receptor (SORL1) expression and function have been implicated in Alzheimers Disease (AD). Here, to gain insights into SORL1, we evaluated SORL1 expression and splicing as a function of AD and AD neuropathology, neural gene expression and a candidate single nucleotide polymorphism (SNP).

Results

To identify SORL1 splice variants, we scanned each of the 46 internal SORL1 exons in human brain RNA samples and readily found SORL1 isoforms that lack exon 2 or exon 19. Quantification in a case-control series of the more abundant isoform lacking exon 2 (delta-2-SORL1), as well as the "full-length" SORL1 (FL-SORL1) isoform containing exon 2 showed that expression of FL-SORL1 was reduced in AD individuals. Moreover, FL-SORL1 was reduced in cognitively intact individuals with significant AD-like neuropathology. In contrast, the expression of the delta-2-SORL1 isoform was similar in AD and non-AD brains. The expression of FL-SORL1 was significantly associated with synaptophysin expression while delta-2-SORL1 was modestly enriched in white matter. Lastly, FL-SORL1 expression was associated with rs661057, a SORL1 intron one SNP that has been associated with AD risk. A linear regression analysis found that rs661057, synaptophysin expression and AD neuropathology were each associated with FL-SORL1 expression.

Conclusion

These results confirm that FL-SORL1 expression declines in AD and with AD-associated neuropathology, suggest that FL-SORL1 declines in cognitively-intact individuals with AD-associated neuropathology, identify a novel SORL1 splice variant that is expressed similarly in AD and non-AD individuals, and provide evidence that an AD-associated SNP is associated with SORL1 expression. Overall, these results contribute to our understanding of SORL1 expression in the human brain.

Sex-dependent association of a common low-density lipoprotein receptor polymorphism with RNA splicing efficiency in the brain and Alzheimer's disease

Since apoE allele status is the predominant Alzheimer's disease (AD) genetic risk factor, functional single nucleotide polymorphisms (SNPs) in brain apoE receptors represent excellent candidates for association with AD. Recently, we identified a SNP, rs688, as modulating the splicing efficiency of low-density lipoprotein receptor (LDLR) exon 12 in female human liver and in minigene-transfected HepG2 cells. Moreover, the rs688T minor allele was associated with significantly higher LDL and total cholesterol in women within the Framingham Offspring Study cohort. Since LDLR is a major apoE receptor in the brain, we hypothesized that rs688 modulates LDLR splicing in neural tissues and associates with AD. To evaluate this hypothesis, we first transfected LDLR minigenes into SH-SY5Y neuroblastoma cells and found that the rs688T allele reduces exon 12 inclusion in this neural model. We then evaluated the association of rs688 allele with exon 12 splicing efficiency in vivo by quantifying LDLR splicing in human anterior cingulate tissue obtained at autopsy; the rs688T allele is associated with decreased LDLR exon 12 splicing efficiency in aged males, but not females. Lastly, we evaluated whether rs688 associates with AD by genotyping DNA from 1457 men and 2055 women drawn from three case-control series. The rs688T/T genotype was associated with increased AD odds in males [recessive model, odds ratio (OR) of 1.49, 95% confidence interval (CI) of 1.13-1.97, uncorrected P = 0.005], but not in females. In summary, these studies identify a functional apoE receptor SNP that is associated with AD in a sex-dependent fashion.

A common polymorphism decreases low-density lipoprotein receptor exon 12 splicing efficiency and associates with increased cholesterol

Single nucleotide polymorphisms (SNPs) that alter exon splicing efficiency are an emerging class of functional genetic variants. Since mutations in low-density lipoprotein receptor (LDLR) are a primary cause of familial hypercholesterolemia, we evaluated whether LDLR SNPs may alter splicing efficiency and cholesterol homeostasis. A SNP within LDLR exon 12, rs688, was identified in silico as neutralizing a putative exon splicing enhancer. Studies in human liver samples established that this SNP was associated with significantly decreased LDLR exon 12 splicing efficiency in women in vivo. In vitro minigene splicing studies qualitatively replicated these in vivo results and demonstrated that rs688 specifically modulates splicing efficiency. These effects on splicing may be physiologically relevant because the presence of the rs688 minor allele associates with increased total and LDL-cholesterol in female members of the Framingham Offspring Study. The largest rs688-associated cholesterol differences were observed in pre-menopausal women. In summary, these studies identify an LDLR SNP present in approximately 60% of Caucasians that is associated with significant 10% increases in total and LDL-cholesterol in pre-menopausal women.

Uterine effects of tamoxifen: a prospective study

The purpose of the study was to evaluate tamoxifen-associated changes in the vagina and uterus in postmenopausal breast cancer patients. Between June 1994 and December 1998, 45 patients enrolled in a prospective study before commencing tamoxifen therapy. Patients with endometrial thickness >5 mm or neoplasia were excluded. Transvaginal ultrasonography, vaginal maturation indexes (VMI), and endometrial biopsy were performed at baseline and repeated at 6 months (n= 42), 1 year (n= 39), 2 years (n= 32), 3 years (n= 26), 4 years (n= 19), and 5 years (n= 15). For the 39 patients followed for 1 year, VMI (% parabasal/intermediate/superficial) was 21/71/8 at baseline compared with 1/90/9 at 1 year (P value = 0.0008/0.001/0.78). At baseline, mean endometrial thickness and uterine volume were 2.6 mm and 64 cm(3), respectively, compared with 5.8 mm and 84 cm(3) at 1 year (P= 0.0002, 0.002). At baseline, 80% of patients had atrophic endometrium and 9% proliferative endometrium compared with 61% and 26% at 1 year, respectively (P= 0.04). No cases of endometrial hyperplasia or adenocarcinoma were detected. Findings observed at 6 months persisted through 5 years of follow-up. Tamoxifen exerts a weak estrogenic effect on the vagina and uterus in highly prescreened postmenopausal women without preexisting endometrial pathology.

Predictors of long-term outcome following high-dose chemotherapy in high-risk primary breast cancer

We report on a predictive model of long-term outcome in 114 high-risk breast cancer patients treated with high-dose chemotherapy between 1989 and 1994. Paraffin-blocks from 90 of the 114 primaries were assessed for the presence of five risk factors: grade, mitotic index, protein expression of p53, HER2/neu, and oestrogen/progesterone receptor status; we could analyse the effect of risk factors in 84 of these 90 tumours. Seven-year relapse-free and overall survival was 58% (95% confidence interval 44-74%) and 82% (95% confidence interval 71-94%) vs 33% (95% confidence interval 21-52%) and 41% (95% confidence interval 28-60%) for patients whose primary tumours displayed > or =3 risk factors vs patients with < or =2 risk factors. For the entire group of 168 high-risk breast cancer patients, inflammatory stage IIIB disease and involved post-mastectomy margins were associated with decreased relapse-free survival and overall survival; patients treated with non-doxorubicin containing standard adjuvant therapy experienced worse overall survival (RR, 2.08; 95% confidence interval 1.04 to 4.16; P=0.04), while adjuvant tamoxifen improved overall survival (RR, 0.65; 95% confidence interval 0.41-1.01; P=0.054). Future trial designs and patient selection for studies specific for high-risk breast cancer patients should include appropriate prognostic models. Validation of such models could come from recently completed randomised, prospective trials.

Epidermal growth factor receptor (HER1) tyrosine kinase inhibitor ZD1839 (Iressa) inhibits HER2/neu (erbB2)-overexpressing breast cancer cells in vitro and in vivo

Aberrrant signaling by the epidermal growth factor receptor [EGFR (HER1, erbB1)] and/or HER2/neu tyrosine kinases is present in a cohort of breast carcinomas. Because HER2 is constitutively phosphorylated in some breast tumors, we speculated that, in these cancers, transmodulation of HER2 may occur via EGFR signaling. To test this possibility, we examined the effect of EGFR-specific kinase inhibitors against the HER2-overexpressing human breast tumor lines BT-474, SKBR-3, MDA-361, and MDA-453. ZD1839 (Iressa) is an ATP-mimetic that inhibits the purified EGFR and HER2 kinases in vitro with an IC(50) of 0.033 and >3.7 microM, respectively. The specificity of ZD1839 against EGFR was confirmed in Rat1 fibroblasts transfected with EGFR or HER2 chimeric receptors activated by synthetic ligands without the interference of endogenous receptors. Treatment of all breast cancer cell lines (except MDA-453) with 1 microM ZD1839 almost completely eliminated HER2 phosphorylation. In contrast, the incorporation of [gamma-(32)P]ATP in vitro onto HER2 receptors isolated from BT-474 cells was unaffected by 1 microM ZD1839. EGFR is expressed by BT-474, SKBR-3, and MDA-361 but not by MDA-453 cells, suggesting that ZD1839-mediated inhibition of the EGFR kinase explained the inhibition of HER2 phosphorylation in vivo. In SKBR-3 cells, ZD1839 exhibited a greater growth-inhibitory effect than Herceptin, a monoclonal antibody against the HER2 ectodomain. In both SKBR-3 and BT-474 cells, treatment with ZD1839 plus Herceptin induced a greater apoptotic effect than either inhibitor alone. Finally, ZD1839 completely prevented growth of BT-474 xenografts established in nude mice and enhanced the antitumor effect of Herceptin. These data imply that EGFR tyrosine kinase inhibitors will be effective against HER2-overexpressing breast tumor cells that also express EGFR and support their use in combination with HER2 antibodies, such as Herceptin, against mammary carcinomas with high levels of the HER2 proto-oncogene.

Pathology of preinvasive and excellent prognosis breast cancer

We review recent reports on breast cancer and its predictors, emphasizing the clinical utility of tissue samples from patients. We highlight indicators of increased cancer risk and lesions without metastatic capacity at time of detection, but of sufficient risk of attaining metastatic capacity that treatment is mandated ( ie, ductal carcinoma in situ ). Emphasized are histologic features of importance in stratification of ductal carcinoma in situ. We also review invasive lesions with little capacity for metastatic behavior and indicators of low malignant potential. Included are several papers reviewing the usefulness of histologic grading, emphasizing mitotic counts. Also, the continuing utility of recognizing some special and unusual types of breast cancer is detailed. Sentinel lymph node evaluation by histology is included because some minimal or artifactual findings in lymph nodes can mimic true metastases.

Core biopsy of the breast with atypical ductal hyperplasia: a probabilistic approach to reporting

The diagnosis of atypical ductal hyperplasia (ADH) at needle core breast biopsy (NCB) is typically regarded as an indication for surgical excision. Although ADH is an intermediate risk nonobligate precursor lesion, the rationale for further therapy is the result of a reported high prevalence of a concomitant more advanced lesion (typically ductal carcinoma in situ) as the index lesion. To assess whether certain histopathologic features of ADH in NCB are predictive of open biopsy outcomes, the authors correlated the extent and pattern of ADH in 47 core biopsies (11-or 14-gauge) with the subsequent surgical specimen. Extent of ADH on NCB was ascertained by determining the number of large ducts and/or terminal duct-lobular units affected, with involvement of one large duct or one terminal duct-lobular unit representing a single focus, involvement of one duct and one terminal duct-lobular unit as two foci, and so on. Of the 47 cases, ADH was restricted to < or =2 foci in 24 cases (51.1%), confined to 3 foci in 8 cases (17.0%), and involved > or =4 foci in 15 cases (31.9%). The corresponding histopathologic findings at excision were benign lesions without atypia (n = 14), focal residual ADH (n = 13), atypical lobular hyperplasia (n = 3), ductal carcinoma in situ (n = 15), and invasive mammary carcinoma (n = 2). When the number of foci of involvement by ADH on NCB (based on an average of 11.6 cores per case) was correlated with the open biopsy results, all cases of ADH limited to < or =2 foci had no worse lesion on excision, whereas ADH present in > or =4 foci was found to be a strong predictor of a more advanced lesion on excision (p <0.0001, chi2). When histologic pattern was evaluated, all cases of pure micropapillary ADH on NCB showed pure micropapillary ductal carcinoma in situ on excision.

Atypical ductal hyperplasia and ductal carcinoma in situ of the breast associated with perineural invasion

Perineural invasion is a histologic feature usually diagnostic of invasion in malignancies. In the breast, however, it has been associated with benign lesions such as sclerosing adenosis (SA), complex sclerosing lesion/radial scar (CSL/RS), and ductal carcinoma in situ (DCIS). This article describes perineural invasion associated with atypical ductal hyperplasia (ADH), florid hyperplasia without atypia (FH), and DCIS. All cases with a diagnosis of perineural invasion were selected from a series of 10,000 breast consult cases. Invasive mammary carcinomas were excluded. Fourteen cases of perineural invasion were found and associated with the following diagnoses: ADH (5), DCIS (3), FH (5), and ductal adenoma (1). Nine cases developed in CSL/RS, 4 cases in SA, and 1 case in a previous biopsy site of ductal adenoma; lesions were all less than 3 mm. The glands involving nerves showed cytologic and architectural features of the adjacent ADH, DCIS, and FH. Immunostaining for protein gene product (PGP) 9.5 marked nerves, and smooth muscle actin antibody highlighted the myoepithelial cells around glands. Perineural invasion seen in association with DCIS and ADH, in a background of CSL/RS and SA, may pose difficulty in diagnosis, especially in small biopsy specimens. It should be assessed with care to avoid misinterpretation as invasive mammary carcinoma.

No elevation in long-term breast carcinoma risk for women with fibroadenomas that contain atypical hyperplasia

BACKGROUND

The authors previously showed that women with a fibroadenoma have a relative risk of invasive breast carcinoma of approximately 2.0 compared with women of similar age from the general population. This relative risk approaches 1.0 when family history and proliferative changes in the adjacent parenchyma are removed and rises to > 3.0 if the fibroadenoma has complex histology. The risk for developing breast carcinoma in women with atypical lobular hyperplasia (ALH) and atypical ductal hyperplasia (ADH) or their minimal variants within a fibroadenoma is unknown.

METHODS

The authors conducted a long-term, retrospective cohort study of 1834 women with adequate follow-up who presented with fibroadenoma at three local hospitals between 1950 and 1968. Histology was reviewed using established criteria, and the patients were categorized with ALH, ADH, minimal atypia, or no atypia.

RESULTS

The overall prevalence of ALH or ADH within fibroadenomas was 0.81%. Minimal or true atypia within a fibroadenoma appeared to be correlated with proliferative disease in the adjacent parenchyma but could not predict for the presence there of well-established atypia. Only 7% of women with well-developed atypia developed invasive carcinoma on follow-up. Three women with minimal atypia developed invasive carcinoma.

CONCLUSIONS

In this study of a large cohort of women with fibroadenoma, the authors found that atypia within a fibroadenoma cannot predict for the presence of atypia within adjacent breast parenchyma. They also found that atypia confined to a fibroadenoma does not incur a clinically meaningful risk of future breast carcinoma development greater than that of fibroadenoma alone.

Pathology of preinvasive and excellent-prognosis breast cancer

Our review of recent developments in breast cancer emphasizes clinical utility of tissue samples from patients. We highlight indicators of increased cancer risk and lesions without metastatic capacity at time of detection (but of sufficient risk of attaining metastatic capacity that treatment is mandated, ie, ductal carcinoma in situ). This review also includes invasive lesions with little capacity for metastatic behavior and indicators of low malignant potential. Histologic criteria for their recognition, as well as biologic and clinical characterization, are discussed. Several papers reviewing the usefulness of histologic grading, emphasizing mitotic counts and definitions of microinvasion, are included.

Inhibition of HER2/neu (erbB-2) and mitogen-activated protein kinases enhances tamoxifen action against HER2-overexpressing, tamoxifen-resistant breast cancer cells

HER2/neu (erbB-2) overexpression has been causally associated with tamoxifen resistance in human breast cancer cells. Forced expression of HER2 in MCF-7 breast cancer cells resulted in mitogen-activated protein kinase (MAPK) hyperactivity and tamoxifen resistance. Inhibition of HER2 and MAPKs with AG1478 and U0126, respectively, as well as dominant-negative MEK-1/2 constructs restored the inhibitory effect of tamoxifen on estrogen receptor (ER)-mediated transcription and cell proliferation. Both AG1478 and U0126 also restored the tamoxifen-mediated association of ER with nuclear receptor corepressor (N-CoR) in the antiestrogen-resistant MCF-7 cells. Treatment with a combination of tamoxifen and a HER2 kinase inhibitor reduced tumor MAPK activity and markedly prevented growth of HER2-overexpressing MCF-7 xenografts in athymic mice. Thus, blockade of HER2 and MAPK signaling may enhance tamoxifen action and abrogate antiestrogen resistance in human breast cancer.

Historical and epidemiologic background of human premalignant breast disease

Premalignant breast disease in humans is a concept that admits to a broad range of elements and possible determinants predicting the likelihood of developing breast cancer. Most of these elements are relative, such as the risk of breast cancer for women that is 130 times that of men and peaks at a younger age by about 10 years. Breast cancer is clearly a stochastic, multifactorial process that evolves over many years in which we must make predictions by likelihood. This review will present the most specially defined and reliably proven of these elements, highlighting anatomic and molecular factors.

Blockade of the epidermal growth factor receptor tyrosine kinase suppresses tumorigenesis in MMTV/Neu + MMTV/TGF-alpha bigenic mice

Overexpression of ErbB-2/Neu has been causally associated with mammary epithelial transformation. Here we report that blockade of the epidermal growth factor receptor (EGFR) kinase with AG-1478 markedly delays breast tumor formation in mouse mammary tumor virus (MMTV)/Neu + MMTV/transforming growth factor alpha bigenic mice. This delay was associated with inhibition of EGFR and Neu signaling, reduction of cyclin-dependent kinase 2 (Cdk2) and mitogen-activated protein kinase (MAPK) activities and cyclin D1, and an increase in the levels of the Cdk inhibitor p27(Kip1). In addition, BrdUrd incorporation into tumor cell nuclei was prevented with no signs of tumor cell apoptosis. These observations prompted us to investigate the stability of p27. Recombinant p27 was degraded rapidly in vitro by untreated but not by AG-1478-treated tumor lysates. Proteasome depletion of the tumor lysates, addition of the specific MEK1/2 inhibitor U-0126, or a T187A mutation in recombinant p27 all prevented p27 degradation. Cdk2 and MAPK precipitates from untreated tumor lysates phosphorylated recombinant wild-type p27 but not the T187A mutant in vitro. Cdk2 and MAPK precipitates from AG-1478-treated tumors were unable to phosphorylate p27 in vitro. These data suggest that increased signaling by ErbB receptors up-regulates MAPK activity, which, in turn, phosphorylates and destabilizes p27, thus contributing to dysregulated cell cycle progression.

Induction of cytotoxic T cells and their antitumor activity in mice transgenic for carcinoembryonic antigen

In order to develop immunotherapy strategies that are based on eliciting immune responsiveness to the self-antigen, human carcinoembryonic antigen (CEA), we examined whether cytotoxic T lymphocyte (CTL) activity against CEA could be elicited in CEA-transgenic and nontransgenic mice. CEA-transgenic [C57BL/ 6-TGN(CEAGe)18FJP] and nontransgenic mice were primed with CEA-transfected syngeneic fibroblasts in combination with Corynebacterium parvum. Spleen cells from immunized mice were cultured with irradiated syngeneic MC-38 colon carcinoma cells transfected with CEA (MC-38.CEA) as stimulators prior to the measurement of CTL activity. Primed nontransgenic spleen cells showed augmented CTL activity against MC-38.CEA cells as compared with control parental MC-38 cells, nontransfected or transfected with vector only. Moreover, primed CEA transgenic spleen cells showed augmented CTL activity against MC-38.CEA cells that was similar to that observed in nontransgenic mice. All CTL clones derived from either transgenic or nontransgenic mice showed cross-reactivity with MC-38 cells expressing the CEA-related antigen, nonspecific cross-reacting antigen, but not biliary glycoprotein. CEA-specific CTL clones were not identified. Adoptive transfer of cloned CTL resulted in inhibition of MC-38.CEA but not MC-38.BGP tumor growth. Tumor cures were elicited in mice treated with a combination of cloned CTL and cyclophosphamide. Histopathological examination of CEA-expressing colons from either immunized mice or recipients of cloned CTL did not reveal any autoimmune reactions. These studies demonstrate that CTL recognizing cross-reactive class I epitopes on the CEA molecule can be induced in transgenic mice. The expression of these epitopes on tumor cells creates effective targets for CTL in vivo without inducing adverse reactions in CEA-expressing normal tissues. Since anti-CEA CTL have been generated in humans, CEA-transgenic mice may be a useful model to study vaccines that are based on CTL effector mechanisms.

Prognostic factors in breast cancer. College of American Pathologists Consensus Statement 1999

BACKGROUND

Under the auspices of the College of American Pathologists, a multidisciplinary group of clinicians, pathologists, and statisticians considered prognostic and predictive factors in breast cancer and stratified them into categories reflecting the strength of published evidence.

MATERIALS AND METHODS

Factors were ranked according to previously established College of American Pathologists categorical rankings: category I, factors proven to be of prognostic import and useful in clinical patient management; category II, factors that had been extensively studied biologically and clinically, but whose import remains to be validated in statistically robust studies; and category III, all other factors not sufficiently studied to demonstrate their prognostic value. Factors in categories I and II were considered with respect to variations in methods of analysis, interpretation of findings, reporting of data, and statistical evaluation. For each factor, detailed recommendations for improvement were made. Recommendations were based on the following aims: (1) increasing uniformity and completeness of pathologic evaluation of tumor specimens, (2) enhancing the quality of data collected about existing prognostic factors, and (3) improving patient care.

RESULTS AND CONCLUSIONS

Factors ranked in category I included TNM staging information, histologic grade, histologic type, mitotic figure counts, and hormone receptor status. Category II factors included c-erbB-2 (Her2-neu), proliferation markers, lymphatic and vascular channel invasion, and p53. Factors in category III included DNA ploidy analysis, microvessel density, epidermal growth factor receptor, transforming growth factor-alpha, bcl-2, pS2, and cathepsin D. This report constitutes a detailed outline of the findings and recommendations of the consensus conference group, organized according to structural guidelines as defined.

Prognostic value of histologic grade and proliferative activity in axillary node-positive breast cancer: results from the Eastern Cooperative Oncology Group Companion Study, EST 4189

PURPOSE

The identification of a subset of patients with axillary lymph node-positive breast cancer with an improved prognosis would be clinically useful. We report the prognostic importance of histologic grading and proliferative activity in a cohort of patients with axillary lymph node-positive breast cancer and compare these parameters with other established prognostic factors.

PATIENTS AND METHODS

This Eastern Cooperative Oncology Group laboratory companion study (E4189) centered on 560 axillary lymph node-positive patients registered onto one of six eligible clinical protocols. Flow cytometric (ploidy and S-phase fraction [SPF]) and histopathologic analyses (Nottingham Combined Histologic Grade and mitotic index) were performed on paraffin-embedded tissue from 368 patients.

RESULTS

Disease recurred in 208 patients; in 161 (77%), within the first 5 years. Mitotic index and grade were associated with both ploidy and SPF (P </=.01). Within the first 5 years of follow-up, mitotic index (P =.004), grade (P =.004), ploidy (P =. 006), and SPF (P =.05) were associated with time to recurrence; there was also a significant association with survival. The effect of mitotic index was largely a result of the difference between 0 to 2 mitoses/10 high-power fields (HPF; 5-year recurrence of 31%) and more than 2 mitoses/10 HPF (5-year recurrence of 52%). The 0 to 2 mitoses/10 HPF group was independently associated with improved prognosis at 5 years (P =.002) in regression models that included other standard prognostic factors.

CONCLUSION

A subset of axillary lymph node-positive patients with improved prognosis may be identified using a lower (< 3 mitoses/10 HPF) mitotic count than is usually performed.

Diabetic mastopathy. A clinicopathologic review

Diabetic mastopathy, an uncommon form of lymphocytic mastitis and stromal fibrosis, typically occurs in longstanding type 1 diabetes. Nineteen cases meeting predetermined histopathologic criteria for diabetic mastopathy were correlated as to clinical history and disease recurrence. Physical examination revealed palpable discrete masses or diffuse nodularity, both predominantly in the subareolar region. One nonpalpable lesion was detected incidentally during reduction mammoplasty. All cases contained lymphocytic ductitis and lobulitis with varying degrees of keloidal fibrosis, vasculitis, epithelioid fibroblasts, and lymphoid nodule formation. Single mammary lesions were found in 11 patients with type 1 diabetes, 1 with type 2 diabetes, and 3 without diabetes. Four cases were bilateral (3 patients with type 1 and 1 patient with type 2 diabetes). Six of 19 cases recurred (3 ipsilateral, 2 contralateral, and 1 bilateral). We confirm the histopathologic constellation for diabetic mastopathy. However, we question the specificity of these features because of identical findings in patients with type 2 diabetes and nondiabetic patients. We found diabetic mastopathy in men and women, as a solitary mass or bilateral disease, and recurrence in either breast, sometimes multiple. Recognition of potential recurrence is important because it might spare patients with documented diabetic mastopathy from repeated breast biopsies.

Loss of expression of transforming growth factor beta type II receptor correlates with high tumour grade in human breast in-situ and invasive carcinomas

AIMS

Loss of transforming growth factor beta type II receptor (TGFbeta-RII) expression has been associated with resistance to TGFbeta-mediated inhibition of cell proliferation and tumour progression. We investigated whether the expression of TGFbeta-RII is related to the progression of human breast cancer and whether there is a correlation between TGFbeta-RII expression and phenotypic markers of biological aggressiveness.

METHODS AND RESULTS

Immunohistochemical methods were used to detect TGFbeta-RII in archival breast samples including benign proliferative lesions, ductal carcinoma in situ (DCIS) and invasive mammary carcinomas (IMC). Neoplastic cells showed reduced expression of TGFbeta-RII in comparison to the normal breast tissue and benign lesions. There was a significant inverse correlation between loss of TGFbeta-RII expression and tumour grade within both DCIS (P = 0.004) and IMC (P = 0.001) groups. There was an inverse correlation between TGFbeta-RII expression and both mitotic count (P = 0.001) and clinical stage (P = 0.004). Oestrogen receptor (P = 0.07) and lymph node status (P = 0.10) were not significantly associated with TGFbeta-RII expression.

CONCLUSIONS

These data indicate that decreased expression of TGFbeta-RII may contribute to breast cancer progression and is related to a more aggressive phenotype in both in-situ and invasive carcinomas.

Reactive spindle cell nodules of the breast after core biopsy or fine-needle aspiration

Reactive spindle cell nodules (RSCNs) arising postoperatively or after fine-needle aspiration (FNA) have been reported previously in the genitourinary tract and thyroid. We describe 18 cases of similar lesions in breast, associated with a history of core needle biopsy or FNA. The majority of the RSCNs (15 cases) were associated with papillary lesions or complex sclerosing lesions. The RSCNs were nonencapsulated and relatively nodular, measuring 1.5 to 9 mm. They were composed of spindle cells with mild to moderate nuclear pleomorphism and a low mitotic count. A network of small blood vessels, macrophages, and lymphocytes was present in all cases. Immunohistochemically, the spindle cells expressed smooth and specific muscle actins, supporting a myofibroblastic origin. The association of RSCNs with needle trauma to fibrosclerotic lesions, such as complex sclerosing lesions and papillary lesions that regularly have myofibroblasts, suggests an exuberant reparative cause. Recognition of this reactive process will avoid overdiagnosis of mammary spindle cell malignant neoplasm.

Loss of expression of transforming growth factor beta type II receptor correlates with high tumour grade in human breast in-situ and invasive carcinomas

AIMS

Loss of transforming growth factor beta type II receptor (TGFbeta-RII) expression has been associated with resistance to TGFbeta-mediated inhibition of cell proliferation and tumour progression. We investigated whether the expression of TGFbeta-RII is related to the progression of human breast cancer and whether there is a correlation between TGFbeta-RII expression and phenotypic markers of biological aggressiveness.

METHODS AND RESULTS

Immunohistochemical methods were used to detect TGFbeta-RII in archival breast samples including benign proliferative lesions, ductal carcinoma in situ (DCIS) and invasive mammary carcinomas (IMC). Neoplastic cells showed reduced expression of TGFbeta-RII in comparison to the normal breast tissue and benign lesions. There was a significant inverse correlation between loss of TGFbeta-RII expression and tumour grade within both DCIS (P = 0.004) and IMC (P = 0.001) groups. There was an inverse correlation between TGFbeta-RII expression and both mitotic count (P = 0.001) and clinical stage (P = 0.004). Oestrogen receptor (P = 0.07) and lymph node status (P = 0.10) were not significantly associated with TGFbeta-RII expression.

CONCLUSIONS

These data indicate that decreased expression of TGFbeta-RII may contribute to breast cancer progression and is related to a more aggressive phenotype in both in-situ and invasive carcinomas.

Benign transport of breast epithelium into axillary lymph nodes after biopsy

The most important prognostic indicator of distant metastasis in breast cancer is histologic documentation of axillary lymph node metastasis. Controversy exists about the importance of micrometastases (< 0.2 cm), and current pathology practice includes a careful search for their presence. We describe the histologic findings in a series of axillary lymph node dissections taken approximately 2 weeks after breast biopsy. Each case has limited presence of epithelial cells in the subcapsular sinus of a draining lymph node that we attribute to mechanical transport of tumor and/or normal breast epithelium secondary to the previous surgical or needle manipulation. These cells were accompanied by hemosiderin-laden macrophages and damaged RBCs. While the clinical implication of these findings is unknown, we believe that it will be of no clinical significance and have no untoward prognostic effect.

Androgen receptor CAG repeat lengths in ductal carcinoma in situ of breast, longest in apocrine variety

CAG repeat number in the androgen receptor (AR) has been associated with decreased prostate cancer risk, and AR expression has been found in female breast cancer, often associated with apocrine differentiation. Because trinucleotide expansion can alter gene expression and protein function, we hypothesized that it might occur in breast neoplasms. We used a repeat expansion detection technique to determine CAG repeat lengths in DNA from breast biopsies. Three lesion types were microdissected: fibroadenoma (48 cases), ductal carcinoma in situ (DCIS, 24 cases), and invasive mammary carcinoma (18 cases). The maximum number of CAG repeats in either allele of each patient in these three groups was compared. Microsatellite repeat lengths in DCIS were longer than in fibroadenomas or invasive carcinomas (P= 0.017 comparing DCIS vs invasive carcinomas). Two cases of apocrine DCIS had very long repeat lengths, both exhibiting microsatellite lengths at the longest range of normal (32 and 33). Inherited differences in AR CAG length might influence the transition from DCIS to invasive breast cancer, perhaps by modulating function of AR in breast tissue. AR microsatellite polymorphisms could influence cellular differentiation in DCIS lesions, promoting formation of the apocrine subtype in the presence of longer CAG repeats.

Transforming growth factor-beta and breast cancer risk in women with mammary epithelial hyperplasia

BACKGROUND

Transforming growth factors-beta (TGF-betas) regulate mammary epithelial cell division. Loss of expression of TGF-beta receptor II (TGF-beta-RII) is related to cell proliferation and tumor progression. Breast epithelial hyperplastic lesions lacking atypia (EHLA) are associated with a mild elevation in breast cancer risk. We investigated the expression of TGF-beta-RII in EHLA and the risk of subsequent invasive breast cancer.

METHODS

We conducted a nested case-control study of women with biopsy-confirmed EHLA who did not have a history of breast cancer or atypical hyperplasia of the breast. Case patients (n = 54) who subsequently developed invasive breast cancer were matched with control patients (n = 115) who did not. Formalin-fixed, paraffin-embedded sections of breast biopsy specimens of all 169 patients with EHLA were studied by immunohistochemical analysis with antibodies against TGF-beta-RII. All P values are two-sided.

RESULTS

Women with breast EHLA and 25%-75% TGF-beta-RII-positive cells or less than 25% TGF-beta-RII-positive cells had odds ratios of invasive breast cancer of 1.98 (95% confidence interval [CI] = 0.95-4.1) or 3.41 (95% CI = 1.2-10.0), respectively (P for trend =.008). These risks are calculated with respect to women with EHLA that had greater than 75% TGF-beta-RII expression. Women with a heterogeneous pattern of TGF-beta-RII expression in their normal breast lobular units and either greater than 75%, 25%-75%, or less than 25% positive cells in their EHLA had odds ratios for breast cancer risk of 0.742 (95% CI = 0.3-1.8), 2.85 (95% CI = 1.1-7.1), or 3.55 (95% CI = 1.0-10.0), respectively (P for trend =.003). These risks are relative to women with a homogeneous pattern of expression in their normal lobular units and greater than 75% positive cells in their EHLA.

CONCLUSION

This study indicates that loss of TGF-beta-RII expression in epithelial cells of EHLA is associated with increased risk of invasive breast cancer.

Pathology of preinvasive and excellent-prognosis breast cancer

Evaluation of tissue and cellular samples for diagnosis, risk assessment, and prognosis in breast cancer is the subject of this review. We emphasize indicators of elevated risk for breast cancer and carcinomas in situ and indicators of good prognosis in invasive breast cancer. The importance of ductal carcinoma in situ to considerations in breast conservation and prevention is highlighted. Special types of breast cancer, immunohistochemistry, histologic grading, and the relevance of core biopsy to diagnostic certainty are considered. We also add a brief note about the escalating role of nodal micrometastases and sentinel node biopsy in the definition of minimal regional disease.

Ovarian histopathology in breast cancer patients receiving tamoxifen

OBJECTIVE

The purpose of this study was to examine ovarian histopathology in tamoxifen-treated breast cancer patients undergoing oophorectomy.

METHODS

We reviewed the records and ovarian histopathology of 152 breast cancer patients who underwent oophorectomy at a single institution between January 1980 and October 1996. At the time of oophorectomy, 99 patients had never received tamoxifen, 44 patients were currently receiving tamoxifen, and 9 patients had previously received tamoxifen. Patient demographic and medical data and indication for oophorectomy were examined. Ovarian histopathology was classified as normal, functional ovarian cyst, benign ovarian tumor, endometriosis, ovarian cancer, and metastatic cancer.

RESULTS

Patient characteristics and indication for oophorectomy did not differ significantly based on tamoxifen exposure. There was no difference in the occurrence of benign ovarian tumors, functional ovarian cysts, or metastatic breast cancer based on tamoxifen exposure. Tamoxifen-treated patients were less likely to have ovarian cancer, 0 of 53 patients (95% confidence interval (CI): 0.0%, 6.7%) compared with 10 of 99 patients (95% CI: 5.0%, 17.8%) patients not receiving tamoxifen (P = 0.015). Endometriosis was slightly more common in patients currently receiving tamoxifen, but the difference was not statistically significant.

CONCLUSIONS

In women undergoing oophorectomy, there was no evidence that tamoxifen exposure was associated with an increase in benign or malignant primary or metastatic ovarian neoplasm or in functional ovarian cysts. Further study is necessary to better define any association between tamoxifen and endometriosis and the effect of tamoxifen on ovarian cancer risk.

Inflammatory myofibroblastic tumour of the breast: report of a case with giant vacuolated cells

Inflammatory myofibroblastic tumours (IMTs) or inflammatory pseudo-tumours are uncommon lesions of unknown aetiology. The majority of the cases are reported in the lungs of young patients. Extra-pulmonary anatomic locations include the abdomen and pelvis, but rare cases have been described in the breast. We describe an IMT in an 86-year-old female, presenting as a well-circumscribed palpable mass in the left breast. Histologically the remarkable feature was the presence of giant vacuolated cells intermixed with spindle cells and a prominent plasma cell infiltrate immersed in a fibrous hyalinized stroma. Immunohistochemical and electron microscopy studies demonstrated the myofibroblastic nature of the giant vacuolated cells and the spindle cells, and the polyclonal nature of the plasma cells. The morphologic and immunohistochemical findings supported the diagnosis of IMT. The biological behaviour of IMT in this age group is unknown and surgical excision with close mammographic follow-up is considered to be appropriate treatment for this lesion in the breast.

Metaplastic breast tumors with a dominant fibromatosis-like phenotype have a high risk of local recurrence

BACKGROUND

In the current study the authors describe the clinicopathologic characteristics of a low grade variant of spindle cell metaplastic tumors of the breast. Previously these tumors have been considered within a larger group recognized as metaplastic carcinoma, including cases with higher grade features.

METHODS

Breast tumors comprised predominantly of low grade spindle cells, with sparse low grade epithelial elements, were selected. Clinical features as well as macroscopic, microscopic, and immunohistochemical findings were reviewed with emphasis on the biologic behavior and the differential diagnosis from other spindle cell lesions.

RESULTS

Of 30 tumors fulfilling strict criteria, 20 contained squamous or glandular elements associated with the spindle cells. Ten tumors were comprised entirely of low grade spindle cells with limited clustered epithelioid cells. At the periphery, all tumors showed a proliferation of bland spindle cells infiltrating the adjacent parenchyma and mimicking fibromatosis. The epithelioid cells and some spindle cells expressed both vimentin and one or more cytokeratins. Seven of eight patients treated by excisional biopsy developed local recurrence, whereas only one of ten patients treated with wide excisional biopsy developed a local recurrence. No distant or regional metastases occurred.

CONCLUSIONS

The presence of limited clusters of epithelioid cells along with a dominant fibromatosis-like pattern may be unique in the breast. The biologic potential of the fibromatosis-like, spindle cell, metaplastic breast tumors most likely is defined by their major histologic phenotype; they are capable of local recurrence with no demonstrated distant spread or regional metastases, as in pure fibromatosis of the breast.

Routinely available indicators of prognosis in breast cancer

Diagnosis coupled with prognostication is the challenge for and charge of the pathologist. In this time of rapidly developing basic knowledge and increasing sophistication in the evaluation of prognostic information, there has also been an important re-evaluation of the validity, reliability, and relevance of classic histopathology. Also, the precision of and criteria for evaluating tumor size and status of regional lymph nodes is under study. Our emphasis in this review is tissue pathology and further, its practical relevance to patient management. Histopathology remains the basis of diagnosis universally; the addition of other elements will increase precision of prediction, particularly of responsiveness to individual therapies. Histologic grade may be integrated to substratify high and low stage cases into prognostically more useful subsets. Histologic types also interact with size and nodal status to predict patients with excellent prognosis. Further refinement of these parameters may occur by analysis within clinical, pathologic, or therapeutic subsets.

Use of cultured cells as a control for quantitative immunocytochemical analysis of estrogen receptor in breast cancer. The Quicgel method

Variation in tissue fixation, processing, and staining is largely responsible for poor reproducibility of estrogen receptor (ER) immunohistochemistry assays. A frozen, agar-suspended pellet of MCF-7 cells with known ER content was added to each of 55 samples of invasive breast carcinoma (IBC), serving as a control. Image analysis determined percentages of positive area (positive nuclei per total nuclei analyzed) and positive stain (sum of optical density of the positive nuclear area divided by sum of the optical density of all nuclei studied) of MCF-7 cells and IBC. MCF-7 cells had a mean value of 150 fmol/mg of ER by dextran-coated charcoal analysis. Image analysis of MCF-7 cells included with the 55 cases showed a mean positive area of 70.81. Positive staining from the IBC cases ranged from 0 to 98.5. By using the known ER content and the positive area of the MCF-7 cells, a conversion factor was used to translate the positive area of the clinical specimens to a femtomole equivalent, which for the 55 IBCs ranged from 0 to 1,790 (mean, 187). Inclusion of a control with known femtomole quantity of ER provides an internal standard for quality control and ER quantitation.

Effects of tamoxifen on the cytology of the uterine cervix in breast cancer patients

Tamoxifen, a nonsteroidal antiestrogen, is the endocrine therapy of choice for all stages of breast cancer. Because tamoxifen is well tolerated and has minimal side effects, it is currently being evaluated in large scale trials as a chemopreventive agent for women at risk for developing breast cancer. The potential adverse effects of tamoxifen, specifically the development of proliferative lesions of the endometrium, coupled with the prospect of its wider use, places new emphasis on recognizing tamoxifen-associated histologic and cytologic changes in the female genital tract. The current study evaluated cervical smears from 52 breast cancer patients treated with tamoxifen compared with 21 smears from breast cancer patients who had not received tamoxifen. Cytologic diagnoses were classified according to the Bethesda system. The presence of blood, inflammation, and hormonal effect were also assessed. No squamous intraepithelial lesions were identified. A total of 21 of 38 smears (55%) from patients receiving tamoxifen alone and 11 of 14 smears (78%) from women who received tamoxifen in combination with adjuvant cytotoxic chemotherapy showed atypias compared with only 6 of the 21 breast cancer patients (28%) who did not have hormonal therapy. The number of smears showing atypia was equally divided into changes interpreted as benign reactive and atypical squamous cells of undetermined significance (ASCUS). Of the 19 patients whose smears were classified as ASCUS, 13 patients had a subsequent cervical biopsy and none showed dysplasia or diagnostic human papilloma virus changes. Tamoxifen therapy was not associated with an increase in the presence of blood or inflammation, and no discernible alteration in the hormonal state was seen in the cervical smears. We conclude that the use of tamoxifen may be associated with benign squamous atypia in cervical smears and that the atypia is not associated with intraepithelial lesions.

Pathology of preinvasive and excellent prognosis breast cancer

Our review of recent developments in breast cancer involving the evaluation of patients' tissues is aimed at indicators of increased cancer risk (i.e., the atypical hyperplasias) and lesions without metastatic capacity at time of detection, but those lesions with sufficient risk of attaining metastasis that treatment is mandated (i.e., the ductal carcinomas in situ). We also include invasive lesions with little capacity for metastatic behavior, and highlight the histologic criteria for their recognition, as well as their biologic and clinical characterization. Also discussed are advances in the understanding of diagnostic techniques, particularly core needle biopsy.

Expression of biliary glycoprotein (CD66a) in normal and malignant breast epithelial cells

Biliary glycoprotein (BGP, CD66a, or C-CAM-1) is a cell adhesion glycoprotein expressed in colon, liver, and hematopoietic tissues. Four major isoforms (a-d) of BGP are expressed in most epithelial tissues by alternative mRNA splicing from a single gene. Since BGP is down regulated in colon cancer and in premalignant colonic adenomas, it has been of interest to study its expression in other tumors. Using immunohistochemistry with a BGP specific antibody, and mRNA analysis by in situ hybridization, RNase protection, and RT-PCR, we show here that BGP is expressed to the same extent in both normal and malignant breast, demonstrating that BGP is not down regulated in breast cancer. In normal breast, BGP expression is confined to the apical surface of ductal and lobular epithelial cells, while in invasive carcinoma of the breast, BGP is expressed throughout the cytoplasm. In situ hybridization shows a specific pattern of BGP expression in both normal and malignant breast epithelium. RNase protection analysis confirms the immunohistochemistry results and shows no quantitative differences between normal and malignant breast. RT-PCR analysis agrees with these results and shows that only 3 of the 4 major isoforms (a, c, d) of BGP are expressed in normal and malignant breast. Since recent studies by Turbide et al (Cancer Res 57: 2781-2788, 1997) have shown that the ratio of murine BGP isoforms may affect tumor suppression in colonic cancer, it is proposed here that the isoform difference between human breast and colon may account for the observed lack of BGP down-regulation in breast vs colon cancer.

Abnormalities detected on transvaginal ultrasonography in tamoxifen-treated postmenopausal breast cancer patients may represent endometrial cystic atrophy

OBJECTIVE

This study was conducted to examine the histopathologic changes in tamoxifen-treated postmenopausal patients with endometrial thickness > or = 5 mm with transvaginal ultrasonography.

STUDY DESIGN

Thirty-five tamoxifen-treated postmenopausal breast cancer patients underwent transvaginal pelvic ultrasonography with endometrial thickness > or = 5 mm followed by either curettage-hysteroscopy (n = 24), or hysterectomy (n = 11). Endometrial histopathologic findings were examined.

RESULTS

Overall, endometrial polyps were the most common histopathologic finding (23 of 35 patients). Endometrial cystic atrophy was uncommonly detected in patients undergoing curettage-hysteroscopy (1 of 24 patients) compared with patients undergoing hysterectomy (9 of 11 patients). No cases of endometrial cancer or hyperplasia were detected.

CONCLUSIONS

Endometrial polyps were a frequent finding in tamoxifen-treated postmenopausal women who had endometrial thickness > or = 5 mm with the use of transvaginal ultrasonography. Endometrial cystic atrophy may explain "thickened endometrium" on transvaginal ultrasonography in this patient population with no evidence of endometrial polyps, hyperplasia, or adenocarcinoma after surgical evaluation.

Mice transgenic for human carcinoembryonic antigen as a model for immunotherapy

Mice transgenic for the human carcinoembryonic antigen (CEA) gene were prepared for use as a preclinical model for immunotherapy. A 32.6-kb fragment containing the complete human CEA gene and flanking sequences was isolated from a genomic cosmid clone and used to produce transgenic C57BL/6 mice. A homozygous line was established that was designated C57BL/6J-TgN(CEAGe)18FJP. Southern blot analysis showed that this line contained intact copies of the cosmid clone, with approximately 19 integrated copies at one chromosomal location. A mouse-human chimeric anti-CEA monoclonal antibody was used to examine CEA expression by immunohistochemical staining of frozen tissue sections. In the cecum and colon, approximately 20% of the luminal epithelial cells had strong cytoplasmic staining, whereas occasional glands showed intense staining. CEA was also expressed in gastric foveolar cells, whereas small intestine villi had only a few (<1%) positive cells. CEA was not found by immunohistochemistry in other tissues of the digestive tract, nor was it found in a wide range of other tissues or organs. Concordance in results was obtained between immunohistochemistry and analysis of tissue extracts by enzyme immunoassay. The lone exception was the testis, which was positive only by enzyme immunoassay. Expression of human CEA was not observed in tissues derived from nontransgenic mice. The fecal content of CEA in transgenic mice was approximately 100-fold less than that observed for humans. Circulating CEA was not detected. A CEA-transfected syngeneic murine colon carcinoma cell line, MC-38, was prepared that had stable expression of CEA in vitro and in vivo. The molecular size of CEA produced by CEA-transfected MC-38 cells and by the colon of transgenic mice was similar to that obtained with CEA purified from human colon tumors. Anti-CEA antibody appeared in nontransgenic but not transgenic mice bearing transfected MC-38 tumors. These findings demonstrate that CEA distribution and its properties in tissues of mice transgenic for the human CEA gene are similar to that observed in human tissues. As in humans, immune responsiveness to CEA, as reflected by antibody formation, was not detectable in transgenic mice bearing CEA-positive tumors. Thus, CEA transgenic mice may serve as a useful model for studying the efficacy and safety of various immunotherapy strategies directed at this tumor self-antigen.

Maintenance of polarity and a dual cell population in adenoid cystic carcinoma of the breast: an immunohistochemical study

AIMS

Adenoid cystic carcinoma (ACC) of the breast, although quite uncommon, is histologically distinct and has an excellent prognosis. Our purpose was to characterize molecular markers of cellular differentiation and polarity to define better the role that these combined features might play in the excellent prognosis of ACC in this site.

METHODS AND RESULTS

We performed immunohistochemical stains for expression of vimentin (VM), cytokeratin (CK), smooth muscle actin (SMA), laminin (LAM), E-cadherin (E-cad), beta-catenin (beta-cat) and fodrin in 14 examples of ACC. Two types of intercellular lumens and defining lining cells were detected: true epithelial lumens were lined by CK positive cells that maintained the normal glandular luminal cells with an intact polarity and basolateral membrane compartment indicators: fodrin, E-cad and beta-cat. The second type of intercellular space was a pseudolumen, surrounded by myoepithelial cells that were strongly positive for VM and SMA, and lined by LAM. Double staining for VM and CK, VM and SMA, and CK and SMA detected occasional cytoplasmic co-expression of these markers in the myoepithelial cell compartment, but VM and SMA did not stain epithelial lumenal cells.

CONCLUSIONS

ACC of the breast is characterized by the presence of two types of intercellular lumens, one conserving basolateral markers of normal polarity (epithelial) with the other containing basement membrane material (abutted by myoepithelial cells). Dominance of VM staining may be a hallmark of ACC, along with maintained epithelial and myoeithelial compartments. This status of advanced, normal differentiation despite local invasion may be responsible for lack of distant metastasis.