[Telemedicine: a Proxemics tool of Primary Care?]

The impact of demographic and sociopolitical phenomena such as population aging, economic and social changes derivinf from globalization and the pervasiveness of information technologies, require innovative and efficient responses to new health needs, characterized by the increase o in the numer of healthcare procedures and its complexity. The COVID 19 has had a negative impact on the that context. This paper demonstrates that the telemdicine enables to optimize resources, as well as to ensure the distancing and delivery times of services. The telemedicine in the time of COVID is the new proxemics tool of Primary care.

Abstract P1-06-03: Serial evolution of hormone receptor status and mutational profile among patients with metastatic breast cancer

Introduction: Tumor heterogeneity presents a significant impediment to identifying appropriate treatments for patients. Genetic mutations and hormone receptors are frequently used as a guide for selecting appropriate targeted or hormonal therapies, however it is possible that these markers may change over time, leading to reduced effectiveness of these treatments. In this study, we review the results of serial and paired biopsies to identify receptor switch in estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status as well as to identify changes in clinically relevant mutations, including spatial and temporal heterogeneity.

Methods: We identified a total of 237 patients initially presenting with ER+/HER2 negative breast cancer and who had multiple biopsies during the course of their treatment, including at least one in the metastatic setting. ER, PR, and HER2 status for each of these serial biopsies was gathered from chart reviews. HER2 results by both IHC and FISH were collected. PIK3CA mutations were also assessed by Snapshot utilizing multiplexed PCR of common hotspot mutations using DNA derived from formalin-fixed, paraffin-embedded (FFPE) tissue.

Results: From a total of 213 patients with known ER status for multiple serial biopsies, we identified 9.4% (N=20) who had at least one change in ER status over time. From a total of 198 patients who had documented PR status for multiple biopsies, 40.4% (N=80) had at least one change in PR status. Changes in HER2 status were similarly assessed, with 6.7% of patients having at least one change by IHC and 4.4% of patients having at least one change by FISH. Of those patients exhibiting changes in ER status, 6 were noted to have multiple changes over time. Of those with changes in PR status, 18 had multiple changes over time. Changes in hormone receptor status were also noted to occur between serial biopsies in the metastatic setting. A total of 128 patients had ER results available for multiple metastatic specimens, of which 8.6% (N=11) had at least one change in ER status. A total of 116 patients had PR results available for multiple metastatic biopsies, of which 38.8% (N=45) had at least one change in PR status. Changes were also noted in the metastatic setting in HER2 (IHC) with a frequency of 8.7% and in HER2 (FISH) with a frequency of 4.7%. A subset of 108 patients were identified as harboring a mutation in PIK3CA. Within this population, 9.6% of patients had at least one change in ER status over time and 34.1% had at least one change in PR status. 9.0% exhibited at least one change in HER2 (IHC) and 6.5% in HER2 (FISH). Serial changes in genotype, from pre- and post-treatment biopsies, were also detected using NGS based Foundation Medicine platform, including acquired alterations in the ESR1 and PI3K pathway.

Conclusion: Serial changes in hormone receptor status and mutation profile are not uncommon among patients initially diagnosed with ER+/HER2 negative breast cancer, and some patients have been noted to have multiple changes over time. Further studies are needed to understand the mechanistic underpinnings governing the emergence of these alterations and their relationship to therapeutic resistance in breast cancer.

Citation Format: Henderson L, Brachtel E, Fitzgerald D, Gadd M, Specht M, Thabet A, Gurski J, Sgroi D, Moy B, Isakoff S, Bardia A, Juric D. Serial evolution of hormone receptor status and mutational profile among patients with metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-06-03.

Abstract S6-05: Comprehensive comparison of prognostic signatures for breast cancer in TransATAC

Background: A number of prognostic signatures have been developed for the prediction of breast cancer recurrence in the past decade. We have developed two signatures (Clinical Treatment Score (CTS), four immunohistochemical markers (IHC4)) and validated four prognostic signatures (Oncotype Dx Recurrence Score (RS), PAM50-based Prosigna (ROR), Breast Cancer Index (BCI), and EndoPredict (EPclin)) in the TransATAC cohort. Here, we compare the prognostic performance of these six signatures for distant recurrence (DR) in years 0-10, and specifically in years 5-10 after treatment cessation.

Methods: 1231 postmenopausal women with hormone receptor positive and HER2-negative breast cancer had at least one test performed. Of these, 818 women had data on all six signatures available. IHC4, RS and BCI (linear) are molecular only signatures whereas CTS, ROR and EPclin include clinicopathological factors. The primary endpoint was DR and the primary objective was to compare the prognostic value of the six signatures in terms of DR for years 0-10, 0-5, and 5-10. Secondary objectives included the comparison of the prognostic performance for node-negative and node-positive patients separately and the additional prognostic performance of each signature to the others. Likelihood ratio statistics (LR-χ2) were used to assess the prognostic information of each signature alone or in combination with other signatures.

Results: Median follow-up for this analysis was 9.94 years (IQR 8.01-10.09) and a total of 126 DR were recorded. 818 women with HER2-negative disease for whom data of all six signatures were available were included in this analysis. For all patients, CTS and EPclin were the most prognostic signatures in years 0-10 (CTS: LR-χ2=124.9; EPclin: LR-χ2=116.2) and years 5-10 (CTS: LR-χ2=59.6; EPclin: LR-χ2=56.8) in the univariate analysis. The other four signatures performed similarly well in years 0-5, but of those only BCI and ROR provided substantial prognostic information in years 5-10 (BCI: LR-χ2=25.3; ROR: LR-χ2=43.8). In multivariate analyses comparing the added information of the molecular signatures over CTS, IHC4 and BCI provided the most information (IHC4: ΔLR-χ2=19.0; BCI: ΔLR-χ2=19.8). In node-negative patients (72.3%), the ROR showed the most prognostic value in years 0-10 (LR-χ2=48.6) and years 5-10 (LR-χ2=31.3) whereas the RS was least prognostic in this patient group. For patients with node-positive disease (27.7%), the CTS and EPclin were the most prognostic and the other four signatures provided much less prognostic information for this patient population (data not shown).

Conclusion: Overall, the CTS and EPclin were the most prognostic signatures for DR and also added significant prognostic value to the other scores in women with HER2-negative disease, primarily due to the incorporation of nodal status in these signatures. For women with node-negative disease, the ROR, BCI, and EPclin signatures provided most prognostic value whereas for those with positive nodes CTS and EPclin were most prognostic. Our analyses showed that the inclusion of clinic-pathological factors into gene signatures is highly important for deriving an accurate prognostic assessment, particularly in node-positive patients.

Citation Format: Sestak I, Buus R, Cuzick J, Dubsky P, Kronenwett R, Ferree S, Sgroi D, Schnabel C, Baehner R, Mallon E, Dowsett M. Comprehensive comparison of prognostic signatures for breast cancer in TransATAC [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr S6-05.

Abstract P1-07-13: Prognostic relevance of statistically standardized estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) in tamoxifen(TAM)-treated NCIC CTG MA.14 patients

Background: Poor inter-laboratory comparability of common clinically used breast cancer biomarkers led to a proposal of statistical standardization (SS) of laboratory results, similar to bone mineral density (BMD) z-scores. This analysis is the first utilization of SS in a trial where all women received TAM.

Methods: MA.14 allocated 667 postmenopausal women to TAM +/− Octreotide LAR (OCT) based on locally determined ER/PR, without HER2 status. At 9.8 yrs median follow-up, the secondary endpoint of relapse-free survival (RFS) had a non-significant hazard ratio (HR) for TAM-OCT to TAM of 0.87 (95% CI 0.63–1.21; p = 0.40). 299 patients who were representative of MA.14 patients by treatment and stratification factors (exact Fisher p-values=0.19–0.90) had their tumors centrally assessed for ER, PR, and HER2 by RT-PCR. Continuous values were used for SS of each biomarker. Univariate (uni) assessment used similar categorizations as those for BMD, assigning ER/PR/HER2 values by number of standard deviations (SD) about the mean (Group 1, z-score ≥1.0 SD below mean; Group 2, z-score <1.0 SD below mean; Group 3, z-score ≤1.0 SD above mean; Group 4, z-score >1.0 SD above mean). A log-rank statistic was used to test for differences between SS biomarker groups with K-M plots for graphical description. Multivariate (multi) effects of SS biomarkers and baseline patient characteristics on RFS were examined with exploratory (un)stratified Cox step-wise forward regression, adding a factor if likelihood ratio criterion was p ≤ 0.05. Sensitivity analyses used a prior external HER2+ cut-point of ≥1.32 SD.

Results: 292 patient samples passing internal analytical quality control were included in this analysis. Uni analyses indicated SS ER was not associated with RFS (p = 0.31). SS PR had a significant uni effect on RFS [p = 0.03; Group 4 compared to Group 1, HR of 0.33 (95% CI 0.12–0.90); Group 3 compared to Group 1, HR of 0.42 (95% CI 0.21–0.83); and Group 2 compared to Group 1 HR of 0.70 (95%CI 0.36–1.37)]. SS HER2 also had a significant uni effect on RFS [p = 0.004; Group 4 compared to Group 1, HR of 0.90 (95% CI 0.37–2.16)]; Group 3 compared to Group 1, HR of 0.39 (95% CI 0.18–0.84); and, Group 2 compared to Group 1, HR of 0.34 (95% CI 0.16–0.70)]. Multi stratified/unstratified Cox models indicated T1 tumours (p = 0.02/p = 0.0002) and higher SS PR (p = 0.02/0.01) were associated with significantly longer RFS; other unstratified results showed that N-ve patients had better RFS (p < .0001), while local ER/PR status did not impact RFS (p > 0.05). The HER2+ cut-point of ≥1.32 SD indicated directionally worse RFS (uni p-value=0.05; multi p-value=0.06).

Discussion: In MA.14, all women received TAM. Local ER/PR status using categorical or semi-quantitative values did not impact RFS. A statistically standardized approach using continuous centralized ER, PR, HER2 by RT-PCR demonstrated that increasing PR values were associated with better RFS. Evaluation in other trials may provide support for this methodology.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-07-13.

Abstract P2-01-14: circulating tumor cells in breast cancer exhibit dynamic changes in epithelial and mesenchymal cell composition

Epithelial to mesenchymal transition (EMT) has been postulated to contribute to the migration and dissemination of cancer cells, but supporting histopathological evidence is limited. We used a microfluidic device to isolate circulating tumor cells (CTCs), combined with multiplex fluorescent RNA-in-situ hybridization (ISH) and RNA sequencing, to quantify and characterize EMT in breast cancer cells within the bloodstream. Whereas only rare (0.1–10%) cells in the primary tumor expressed both mesenchymal and epithelial markers, such biphenotypic as well as purely mesenchymal cells were enriched among CTCs, across all histological subtypes of breast cancer. Analysis of the therapy response in 8 patients suggest an association of mesenchymal CTCs with disease progression. In an index patient followed longitudinally, fluctuation in epithelial and mesenchymal states was observed as a function of initial response and subsequent resistance to therapy. Mesenchymal markers were predominant in clusters of tumor cells, many of which had adherent platelets. Finally, RNA sequencing of mesenchymal CTC clusters identified TGF-B and other EMT-related signatures, which were absent from more epithelial CTCs. FOXC1, a known regulator of EMT, was abundantly expressed in mesenchymal CTCs and was detectable within localized regions of the primary breast tumor. Together, these data support a role for EMT in the blood-borne dissemination of breast cancer and point to the dynamic nature of this cell fate change.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-01-14.

Prediction of late recurrences by breast cancer index in the NCIC CTG MA.17 cohort

2

Background: The MA.17 trial demonstrated that extended adjuvant endocrine therapy with letrozole after 5-y of tamoxifen markedly reduced the risk of recurrence in women with ER+ early stage breast cancer. This trial provides an opportunity to assess the ability of biomarkers to predict late recurrences in ER+ breast cancer. The Breast Cancer Index (BCI), a continuous risk index based on the combination of HOXB13:IL17BR (H:I) and the molecular grade index (MGI), estimates the individual risk of recurrence in ER+ breast cancer patients. In this study, the prognostic utility of BCI to predict late recurrences was examined.

Methods: FFPE tumor blocks were collected from patients who experienced a breast cancer recurrence up to unblinding of MA.17. Controls were matched 2:1 for age, tumor size, nodal status and prior chemotherapy, and were disease free for longer than cases. All cases were reviewed for standard histopathology and evaluated using the real-time RT-PCR BCI assay.

Results: Patient characteristics for the case-control study were similar to that from the overall study. Characteristics for cases (N=83) and controls (N=166) were not significantly different except for treatment. A higher percentage of controls compared to cases tended to be categorized as low risk by BCI (58% vs 43%), while a lower percentage of controls than cases tended to be categorized as high risk by BCI (34% vs 24%). In univariate analysis, treatment, BCI, H:I and HOXB13, but not tumor grade or MGI, were significant predictors of late recurrence. After adjusting for standard variables (age, tumor grade and treatment), BCI (OR 2.37; P=0.03), H:I (OR 2.55; P=0.04) and HOXB13 (OR 1.35; P=0.02) remained significant predictors of recurrence. HOXB13 expression at diagnosis predicted patient benefit from extended endocrine therapy with letrozole.

Conclusions: In this case-controlled study, the data demonstrate that BCI is a significant predictor of late recurrences in ER+ patients following 5-y of tamoxifen. The prognostic performance of BCI to predict late recurrences was largely dependent on HOXB13 expression. The integration of H:I and MGI within BCI provides prognostic utility for both early and late recurrences.

Rat neonatal beta cells lack the specialised metabolic phenotype of mature beta cells

AIMS/HYPOTHESIS

Fetal and neonatal beta cells have poor glucose-induced insulin secretion and only gain robust glucose responsiveness several weeks after birth. We hypothesise that this unresponsiveness is due to a generalised immaturity of the metabolic pathways normally found in beta cells rather than to a specific defect.

METHODS

Using laser-capture microdissection we excised beta cell-enriched cores of pancreatic islets from day 1 (P1) neonatal and young adult Sprague-Dawley rats in order to compare their gene-expression profiles using Affymetrix U34A microarrays (neonatal, n = 4; adult, n = 3).

RESULTS

Using dChip software for analysis, 217 probe sets for genes/38 expressed sequence tags (ESTs) were significantly higher and 345 probe sets for genes/33 ESTs significantly lower in beta cell-enriched cores of neonatal islets compared with those of adult islets. Among the genes lower in the neonatal beta cells were key metabolic genes including mitochondrial shuttles (malate dehydrogenase, glycerol-3-phosphate dehydrogenase and glutamate oxalacetate transaminase), pyruvate carboxylase and carnitine palmitoyl transferase 2. Differential expression of these enzyme genes was confirmed by quantitative PCR on RNA from isolated neonatal (P2 until P28) and adult islets and with immunostaining of pancreas. Even by 28 days of age some of these genes were still expressed at lower levels than in adults.

CONCLUSIONS/INTERPRETATION

The lack of glucose responsiveness in neonatal islets is likely to be due to a generalised immaturity of the metabolic specialisation of pancreatic beta cells.

HOXB13 May Predict Response to Neoadjuvant Letrozole in Patients with Estrogen Receptor-Positive Breast Cancer

Background. Third generation aromatase inhibitors (AIs) have been shown to be superior to tamoxifen in multiple randomized clinical trials and become the new standard of treatment for postmenopausal women with early or advanced endocrine-sensitive breast cancer. It is thus important to identify biomarkers predicting resistance to AIs so that alternative therapeutic options can be employed. A two gene expression index, HOXB13:IL17BR, and HOXB13 in particular, has been shown to be a negative predictor of clinical benefit from tamoxifen. It is unclear whether HOXB13:IL17BR or HOXB13 is also predictive of AI therapy.Methods. We performed a retrospective analysis of a phase II randomized neoadjuvant study of everolimus+letrozole vs. placebo+letrozole in patients with estrogen receptor-positive breast cancer. Total RNA was extracted from frozen tissue biopsies taken either prior to treatment or after 15 days of treatment. HOXB13:IL13BR and a molecular grade index (MGI) were measured in 107 pre-treatment samples and 111 samples after 15 days of treatment. Antiproliferative response as defined by a ln[Ki767] <1 at day 15 in the samples analyzed was correlated with these gene expression indices.Results. In the placebo+letrozole treatment arm, the antiproliferative response rate was 30% (14/47). Using a pre-specified cutpoint of 0.06, the response rate was 40% for low HOXB13:IL17BR patients, compared to 12% for high HOXB13:IL17BR patients (p=0.05). In the everolimus+letrozole arm, the antiproliferative response rate in the samples analyzed was 55% (33/60), and the response rates for low and high HOXB13:Il17BR patients were 70% and 37% (p=0.02), respectively. When examined separately, high HOXB13 expression was significantly associated with nonresponse to therapy (everolimus+letrozole arm, p=0.02; placebo+letrozle arm, p=0.03), but IL17BR was not (everolimus+letrozole arm, p=0.6; placebo+letrozle arm, p=0.88). As expected, we observed a significant correlation between MGI and Ki67 staining (Spearman r=0.67, p<0.0001).Conclusions. High HOXB13:IL17BR index and high HOXB13 expression may identify a possible subset of patients with estrogen receptor-positive tumor that could be less responsive to aromatase inhibitors such as letrozole. Furthermore, use of MGI may enable rapid assessment of antiproliferative response by fine needle aspiration.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2120.

Comparison of risk stratification by OncotypeDX versus HOXB13/IL17BR index and molecular grade index in 166 estrogen receptor positive patients from multiple institutions

Abstract #1072

Background
 We have previously reported two complementary prognostic markers in breast cancer for predicting risk of recurrence (Ma et al, Clin Cancer Res, 2008): a molecular grade index (MGI) that recapitulates grade 1 and 3 tumors and stratifies grade 2 tumors, and a gene expression index (HOXB13/IL17BR or H/I) that predicts clinical outcome in estrogen receptor positive (ER+) patients and endocrine benefit (Jerevell et al, Breast Cancer Res Treat, 2007). In combination, MGI and H/I define three risk groups: Low risk (low MGI), intermediate risk (low H/I, high MGI) and high risk (high H/I, high MGI). We conducted a study to compare risk stratification by MGI and H/I within samples for which a previous recurrence score (RS) by Oncotype Dx was reported.
 Materials and Methods
 RNA was extracted from formalin-fixed paraffin-embedded sections from all obtainable samples of patients (pts) from five institutions in which a RS was reported MGH, 77pts; Brigham, 48pts; IU, 19pts; UAB, 13pts; Scripps, 9pts. Real-time RT-PCR assays for MGI and H/I were completed and binary results of low and high for both were determined using pre-defined cutpoints. Risk stratification via MGI + H/I for each sample was compared to previously reported RS's (low, intermediate or high).
 Results
 For the 166 pts, 48% had a low, 45% intermediate and 7% high RS's. Overall, risk stratifications by RS versus MGI + H/I were significantly correlated (p < 0.001) with 81% of patients with low RS also having low risk (low MGI). Risk stratification by H/I + MGI reduced intermediate risk via RS by 2.5-fold (45% versus 18%).
 
 Discussion
 In ER+ pts, MGI + H/I produces a significantly smaller group of patients with intermediate risk by re-stratifying a large number of patients with intermediate RS into low and high risk groups. Risk stratification by H/I + MGI in ER+ pts is by measurement of two discrete parameters: endocrine responsiveness (H/I) and proliferative status (MGI). This may allow for more informed treatment decisions by the treating oncologist. Further studies with clinical outcome are required to establish the clinical significance of these different risk stratification methods.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1072.

p63/p73 expression mediates cisplatin sensitivity in a subset of triple-negative primary breast cancer: Implications for a new clinical trial

10522

Background: Triple-negative breast cancer (ER-, PgR- and HER2-negative) has a poor prognosis relative to other subtypes, even with the best available chemotherapy. We recently reported that in squamous cell cancers, p63 promotes survival by direct interaction with and inhibition of p73-dependent apoptosis. We now report on the role of p63/p73 in triple-negative breast cancer. Methods: We performed quantitative RT-PCR on primary breast cancer specimens to determine the expression of specific p63 and p73 isoforms. Cell culture experiments used MCF7, HCC-1937, MDA-MB-468, T47D, and MCF10A cell lines. Lentiviral p63 and p73 shRNA were used for knockdown experiments. Chemotherapy dose-response curves were generated using MTT assay. Results: In primary tumors, ΔNp63 and TAp73 isoforms are expressed exclusively within a subset of triple-negative tumors in which p53 mutations are commonly found. Knockdown of p63 in triple-negative cell lines, but not the ER-positive MCF7 line, induced apoptosis which was specifically dependent on p73 expression. Breast cancer cell lines expressing p63/p73 exhibited p73-dependent sensitivity to cisplatin. Knockdown of p73 resulted in a 10–100 fold increase in the IC50 of cisplatin, but no change in doxorubicin or paclitaxel sensitivity. Exogenous p73 expression in MCF10A cells, which have high levels of p63 but no p73, confers increased sensitivity to cisplatin. Conclusion: These results show that p63/p73expression promotes survival in a subset of breast cancers, and they provide a mechanism for cisplatin sensitivity. These findings suggest that p63/p73 expression may serve as a biomarker to predict cisplatin sensitivity in triple-negative breast cancer. Based on these results, we are conducting a phase II study of 39 patients evaluating cisplatin as first line therapy for metastatic triple-negative breast cancer. The primary endpoints are overall objective response rate and response rate in low versus high p63/p73 expressing subgroups.

No significant financial relationships to disclose.

Spread of human cancer cells occurs with probabilities indicative of a nongenetic mechanism

There has been much uncertainty as to whether metastasis requires mutation at the time of spread. Here, we use clinical data to calculate the probability of the spread of melanoma and breast cancer cells. These calculations reveal that the probability of the spread of cancer cells is relatively high for small tumours (∼1 event of spread for every 500 cells for melanomas of 0.1 mm) and declines as tumours increase in size (∼1 event of spread for every 10⁸ cells for melanomas of 12 mm). The probability of spread of breast cancer cells from the lymph nodes to the periphery is ∼1 event of spread for every 10⁸ cells in the nodal masses, which have a mean diameter of 5 mm, while the probability of spread of cancer cells from the breast to the periphery when the primary masses are 5 mm is also ∼1 event of spread for every 10⁸ cells. Thus, the occurrence of an event of spread from the breast to the lymph nodes appears not to increase the propensity of the progeny of those cells to spread from the lymph nodes to the periphery. These values indicate that the spread of human breast cancer and melanoma cells is unlikely to occur by a mechanism requiring mutation at the time of spread.

HIN-1, a putative cytokine highly expressed in normal but not cancerous mammary epithelial cells

To identify molecular alterations implicated in the initiating steps of breast tumorogenesis, we compared the gene expression profiles of normal and ductal carcinoma in situ (DCIS) mammary epithelial cells by using serial analysis of gene expression (SAGE). Through the pair-wise comparison of normal and DCIS SAGE libraries, we identified several differentially expressed genes. Here, we report the characterization of one of these genes, HIN-1 (high in normal-1). HIN-1 expression is significantly down regulated in 94% of human breast carcinomas and in 95% of preinvasive lesions, such as ductal and lobular carcinoma in situ. This decrease in HIN-1 expression is accompanied by hypermethylation of its promoter in the majority of breast cancer cell lines (>90%) and primary tumors (74%). HIN-1 is a putative cytokine with no significant homology to known proteins. Reintroduction of HIN-1 into breast cancer cells inhibits cell growth. These results indicate that HIN-1 is a candidate tumor suppressor gene that is inactivated at high frequency in the earliest stages of breast tumorogenesis.

A SAGE (serial analysis of gene expression) view of breast tumor progression

To identify molecular alterations involved in the initiation and progression of breast carcinomas, we analyzed the global gene expression profiles of normal mammary epithelial cells and in situ, invasive, and metastatic breast carcinomas using serial analysis of gene expression (SAGE). We identified sets of genes expressed only or most abundantly in a specific stage of breast tumorigenesis or in a certain subtype of tumors through the pair-wise comparison and by hierarchical clustering analysis of these eight SAGE libraries (two/stage). On the basis of these comparisons, we made the following observations: Normal mammary epithelial cells showed the most distinct and least variable gene expression profiles. Many of the genes highly expressed in normal mammary epithelium and lost in carcinomas encoded secreted proteins, cytokines, and chemokines, implicating abnormal paracrine and autocrine signaling in the initiation of breast tumorigenesis. Very few genes were universally up-regulated in all tumors regardless of their stage and histological grade, indicating a high degree of diversity at the molecular level that likely reflects the clinical heterogeneity characteristic of breast carcinomas. Tumors of different histology type and stage had very distinct gene expression patterns. No genes seemed to be specific for metastatic or for in situ carcinomas. We found that the most dramatic and consistent phenotypic change occurred at the normal-to-in situ carcinoma transition. This observation, combined with the fact that many of the genes involved encode secreted, cell-nonautonomous factors, implies that the normal epithelium-to-in situ carcinoma transition may be the most promising target for cancer prevention and treatment.

Elevation of breast carcinoma Nm23-H1 metastasis suppressor gene expression and reduced motility by DNA methylation inhibition

We hypothesize that elevation of Nm23-H1 expression in micrometastatic breast cancer cells may inhibit their metastatic colonization and further invasion, and induce differentiation, thus resulting in a clinical benefit. The current study investigated the possible contribution of DNA methylation to the regulation of Nm23-H1 expression, based on the observation that two CpG islands are present in its promoter. 5-Aza-2'-deoxycytidine (5-Aza-CdR), a DNA methylation inhibitor, increased the Nm23-H1 expression of 5 of 11 human breast carcinoma cell lines in vitro, including 3 of 3 metastatically competent lines. Increased Nm23-H1 expression was accompanied by a reduction in motility in vitro, with minimal effect on proliferation. Both increased Nm23-H1 expression and decreased motility were observed using low (75 nM) concentrations of 5-Aza-CdR. Array analysis of MDA-MB-231 breast carcinoma cells treated with 5-Aza-CdR confirmed the elevation of nm23-H1 mRNA, whereas relatively few other genes exhibited altered expression. Bisulfite sequencing of the two CpG islands in a panel of cell lines and in 20 infiltrating ductal carcinomas revealed that one island (-3090 bp to -3922 bp) exhibited infrequent differential methylation. The data indicate that DNA methylation inhibitors can directly or indirectly cause both elevation of Nm23-H1 expression and decreased function in one aspect of metastasis, motility.

Tumor-influenced amino acid transport activities in zonal-enriched hepatocyte populations

Cancer influences hepatic amino acid metabolism in the host. To further investigate this relationship, the effects of an implanted fibrosarcoma on specific amino acid transport activities were measured in periportal (PP)- and perivenous (PV)-enriched rat hepatocyte populations. Na(+)-dependent glutamate transport rates were eightfold higher in PV than in PP preparations but were relatively unaffected during tumor growth. System N-mediated glutamine uptake was 75% higher in PV than in PP preparations and was stimulated up to twofold in both regions by tumor burdens of 9 +/- 4% of carcass weight compared with hepatocytes from pair-fed control animals. Excessive tumor burdens (26 +/- 7%) resulted in hypophagia, loss of PV-enriched system N activities, and reduced transporter stimulation. Conversely, saturable arginine uptake was enhanced fourfold in PP preparations and was induced twofold only after excessive tumor burden. These data suggest that hepatic amino acid transporters are differentially influenced by cancer in a spatial and temporal manner, and they represent the first report of reciprocal zonal enrichment of system N and saturable arginine uptake in the mammalian liver.

A single N-linked glycosylation site is implicated in the regulation of ligand recognition by the I-type lectins CD22 and CD33

CD22 is an immunoglobulin superfamily B lymphocyte-specific adhesion receptor and a member of the recently identified I-type class of lectins. Recent work has shown that CD22 specifically recognizes sialic acid linked alpha2,6 to terminal N-linked oligosaccharides on selected cell surface glycoproteins. CD22-ligand interaction is regulated by the activity of a beta-galactoside alpha2, 6-sialyltransferase that can inactivate CD22-mediated binding by sialylating the CD22 receptor itself. These observations suggest that N-linked glycosylation sites on the CD22 molecule may play a role in the regulation of CD22-mediated adhesion. In this work we have performed site-specific mutagenesis of potential N-linked glycosylation sites on CD22 in an effort to determine whether they might be involved in ligand recognition. We show that mutation of a single potential N-linked glycosylation site in the first immunoglobulin domain of CD22 completely abrogates ligand recognition. Interestingly, this site is characterized by the sequence NCT, where the cysteine is thought to be involved in an intrachain disulfide bond. Site-directed mutagenesis of similar NC(T/S) motifs in the first or second Ig domains of the I-type lectins myelin-associated glycoprotein, and sialoadhesin did not disrupt their ability to mediate sialic acid binding. In contrast, mutation of a NCS motif in the first Ig domain of the I-type lectin CD33 unmasked its sialic acid binding activity. These observations suggest that a single N-linked glycosylation site located at a similar position in the CD22 and CD33 glycoproteins is critical for regulating ligand recognition by both receptors.

Involvement of collagenous spherulosis by lobular carcinoma in situ. Potential confusion with cribriform ductal carcinoma in situ

We describe five cases in which the cells of lobular carcinoma in situ seemed to form round, regular lumens similar to the cribriform spaces of ductal carcinoma in situ. After careful inspection, we concluded that the spaces indicate the presence of collagenous spherulosis and that this unusual pattern arises through the confluence of lobular neoplasia and spherulosis. We base this conclusion on three lines of evidence. First, attenuated myoepithelial cells, rather than carcinoma cells, form the spaces in question. Immunohistochemical staining for smooth-muscle actin and keratin 8/18 established the myoepithelial nature of these flattened cells because they express the former protein but lack the latter. These results also differentiate the myoepithelial cells from those of conventional in situ carcinomas, which do not contain smooth-muscle actin but virtually always possess keratin 8/18. Second, the material within the spaces looks like the deposits that characterize collagenous spherulosis. They consist of densely eosinophilic protein or radiating, fibrillar ground substances, and they differ in appearance from the disorganized, flocculent mucin and the cellular debris found in some in situ ductal carcinomas. Finally, the neoplastic cells display a loosely cohesive growth pattern that is more in keeping with the properties of lobular neoplasia than ductal carcinoma. Considered together, these three points should distinguish involvement of collagenous spherulosis by lobular neoplasia from cribriform ductal carcinoma in situ. Pathologists must remain alert to this form of mimicry because classification of in situ carcinoma of the breast carries important clinical implications.

Regulation of CD45 engagement by the B-cell receptor CD22

The B-cell receptor CD22 binds sialic acid linked alpha-2-6 to terminal galactose residues on N-linked oligosaccharides associated with several cell-surface glycoproteins. The first of these sialoglycoproteins to be identified was the receptor-linked phosphotyrosine phosphatase CD45, which is required for antigen/CD3-induced T-cell activation. In the present work, we examine the effect of interaction between the extracellular domain of CD45 and CD22 on T-cell activation. Using soluble CD22-immunoglobulin fusion proteins and T cells expressing wild-type and chimeric CD45 forms, we show that engagement of CD45 by soluble CD22 can modulate early T-cell signals in antigen receptor/CD3-mediated stimulation. We also show that addition of sialic acid by beta-galactoside alpha-2,6-sialyltransferase to the CD22 molecule abrogates interactions between CD22 and its ligands. Together, these observations provide direct evidence for a functional role of the interaction between the extracellular domain of CD45 and a natural ligand and suggest another regulatory mechanism for CD22-mediated ligand engagement.

Mutational analysis of CDKN2 (MTS1/p16ink4) in human breast carcinomas

The CDKN2 gene that encodes the cell cycle regulatory protein cyclin-dependent kinase-4 inhibitor (p16) has recently been mapped to chromosome 9p21. Frequent homozygous deletions of this gene have been documented in cell lines derived from different types of tumors, including breast tumors, suggesting that CDKN2 is a tumor suppressor gene involved in a wide variety of human cancers. To determine the frequency of CDKN2 mutations in breast carcinomas, we screened 37 primary tumors and 5 established breast tumor cell lines by single-strand conformation polymorphism analysis. In addition, Southern blot analysis was performed on a set of five primary breast carcinoma samples and five breast tumor cell lines. Two of the five tumor cell lines revealed a homozygous deletion of the CDKN2 gene, but no mutations were observed in any of the primary breast carcinomas. These results suggest that the mutation of the CDKN2 gene may not be a critical genetic change in the formation of primary breast carcinoma.

The B-cell adhesion molecule CD22 is cross-species reactive and recognizes distinct sialoglycoproteins on different functional T-cell sub-populations

CD22 is a B cell lineage restricted cell-surface adhesion glycoprotein which recognizes ligands on human T and B cells and cell lines. A soluble recombinant form of human CD22 (hCD22Rg) has been used to identify and characterize CD22-specific ligands on human T cells, one of which has been shown to be the receptor-linked phosphotyrosine phosphatase CD45. Because CD45 plays a pivotal role in lymphocyte activation, we assessed whether human CD22 might display cross-species reactivity with CD45. In the study presented here we demonstrate that human CD22Rg recognizes several murine cell-surface sialoglycoproteins, including CD45, containing sialic acid in alpha 2,6 linkage. Furthermore, hCD22Rg recognizes different ligands on functionally distinct T helper-cell subpopulations and selectively binds medullary thymocytes in vivo. Our results confirm and extend previous observations that CD22 is a sialic acid-binding lectin which interacts with CD45 and other glycoproteins capable of presenting alpha 2,6-linked sialic acid in a manner that promotes high affinity binding. The cross-species reactivity of CD22 with its ligands underscores the potential physiologic importance of CD22-mediated lymphocyte interactions.

Natural ligands of the B cell adhesion molecule CD22 beta carry N-linked oligosaccharides with alpha-2,6-linked sialic acids that are required for recognition

CD22 beta is a glycoprotein found on the surface of B cells during restricted stages of development. It is believed to play a role in cell-cell interactions and B cell activation. The accompanying paper (Sgroi, D., Varki, A., Braesch-Andersen, S., and Stamenkovic, I. (1993) J. Biol. Chem. 268, 7011-7018) shows that CD22 beta recognizes multiple glycoproteins on the surfaces of T and B cells and that sialylation of these ligands is essential for binding. To identify the structure(s) of the sialylated oligosaccharide(s) recognized by CD22 beta, [3H]glucosamine-labeled glycoproteins were purified from Daudi cells by adsorption onto a CD22 beta recombinant immunoglobulin (CD22 beta Rg) chimera attached to protein A-Sepharose (PAS), and the N-linked oligosaccharides were released by peptide N-glycosidase F. These released oligosaccharides failed to bind to CD22 beta Rg-PAS under the conditions used initially to adsorb the glycoproteins, but their elution from a column of CD22 beta Rg-PAS was significantly retarded. Populations of oligosaccharides with different affinities could be identified by their order of elution. Specific sialidases were used to determine the content of alpha-2,3- and alpha-2,6-linked sialic acid in these different populations and their contribution to binding. Multiantennary oligosaccharides with one alpha-2,6-linked residue bound marginally, and those with two or more bound more tightly. alpha-2,3-Linked sialic acid residues were without effect. Binding did not require divalent cations and was abrogated by mild periodate oxidation of the outer side chain of sialic acid. No marked differences in size or fucose content were found between the populations of high and low affinity oligosaccharides. However, the low affinity population could be partially converted into higher affinity by treatment with beta-galactoside alpha-2,6 sialyltransferase and CMP-sialic acid. Thus, CD22 beta is a mammalian lectin that can recognize specific N-linked oligosaccharide structures containing alpha-2,6-linked sialic acids.

CD22, a B cell-specific immunoglobulin superfamily member, is a sialic acid-binding lectin

The B lymphocyte cell surface receptor CD22 is an adhesion molecule that can mediate binding to several leukocyte subsets. The first CD22 ligand to be identified was the receptor-linked phosphotyrosine phosphatase CD45, but several lines of evidence suggest that CD22 may interact with multiple counter receptors on adjacent lymphocytes. In the present work, we show that in addition to CD45, a soluble CD22-immunoglobulin fusion protein (CD22Rg) recognizes several other distinct lymphocyte sialoglycoproteins. CD22-mediated adhesion is dependent upon the presence of sialic acids on ligands. CD22Rg is observed to bind specifically to a 115-kDa sialoglycoprotein in COS cells transfected with an alpha-2,6-sialyltransferase cDNA, but not in COS cells transfected with unrelated cDNA clones, indicating that at least some CD22-mediated interactions require presentation of sialic acid in an alpha-2,6 linkage by CD22 ligands. In all cases, truncation of the side chain of sialic acids by mild periodate oxidation abolishes recognition by CD22Rg. Direct binding of CD22Rg to lymphoid cells also requires sialic acids and their side chains. Taken together, these observations indicate that CD22 is a sialic acid-binding lectin and may define a novel functional subset of immunoglobulin superfamily adhesion molecules.

CD22-mediated stimulation of T cells regulates T-cell receptor/CD3-induced signaling

Interaction between B lymphocytes and other cell types is mediated in part by the B-cell adhesion molecule CD22. Recent work has suggested one of the T-cell ligands of B cells to be CD45RO, an isoform of the receptor-linked phosphotyrosine phosphatase CD45. Here we demonstrate direct interaction between CD22 and several isoforms of CD45, including CD45RO, and propose that the interaction may participate in regulation of lymphocyte signaling. Cross-linking of CD3 and CD22 T-cell ligands with anti-CD3 antibody and soluble CD22 is shown to block anti-CD3-induced intracellular calcium increase and to inhibit tyrosine phosphorylation of phospholipase C gamma 1. These effects are consistent with those observed upon coligation of CD3 and CD45 with antibody, providing support to the possibility that ligand-mediated stimulation of CD45 may result in modulation of substrate phosphorylation and lymphocyte activation.

The B lymphocyte adhesion molecule CD22 interacts with leukocyte common antigen CD45RO on T cells and alpha 2-6 sialyltransferase, CD75, on B cells

Functional maturation of B lymphocytes correlates with expression of the B lineage-specific cell surface glycoprotein CD22. Two CD22 polypeptides have been characterized and suggested to play a role in B cell-B cell interaction as well as in B cell adhesion to monocytes. In this work we provide evidence that CD22 is directly involved in the cognate interaction between B and T cells. One of the two CD22 polypeptides, CD22 beta, interacts with a specific ligand on a subpopulation of CD4+ T cells. Our results suggest that the T cell ligand of CD22 is CD45RO, an isoform of the leukocyte common antigen class of phosphotyrosine phosphatases associated with the helper T cell phenotype. We further demonstrate that CD22 recognizes a second ligand, CD75, expressed predominantly on activated B cells and shown to be a cell surface alpha 2-6 sialyltransferase.

The protein kinase C inhibitor H-7, inhibits antigen and IL-2-induced proliferation of murine T cell lines

Activation of protein kinase C has been shown to be involved in the activation pathway of many cell types. Recently, a number of investigations have suggested that protein kinase C plays an essential role in T lymphocyte activation. The recent synthesis of the protein kinase inhibitors, H-7 and HA1004, have now made possible a new approach for testing the relevance of protein kinase C in T cell activation and proliferation. We now report that the antigen-induced and interleukin-2-induced proliferation of murine T cell lines can be consistently inhibited by the protein kinase C inhibitor, H-7. HA1004, a somewhat more potent inhibitor of cyclic nucleotide-dependent protein kinases, but a significantly weaker inhibitor of protein kinase C than H-7, demonstrated no consistent inhibition of these T cell responses. These results represent a further demonstration that protein kinase C plays an essential role in the activation of T cells.

T cell lines derived from the spinal cords of mice with experimental allergic encephalomyelitis are self reactive

Experimental allergic encephalomyelitis (EAE) is an animal model of T cell-mediated, central nervous system neuropathology that may be a relevant animal model for multiple sclerosis. EAE is usually induced by sensitization of animals with a xenogeneic myelin basic protein (MBP). Recently, MBP-reactive T cell lines and clones derived from lymphoid tissue of animals with EAE have proved very useful in elucidating certain aspects of the pathogenesis in EAE. However, questions relating to how T cells actually mediate the pathologic changes seen in EAE remain unresolved. We now report for the first time the derivation of long-term, interleukin 2-dependent T cell lines and sublines from a site of pathology in murine EAE--the spinal cord. All of the spinal cord-derived T cell lines and sublines were found to be "autoreactive" in that they responded to self (murine) MBP as well as to the xenogeneic immunogen, porcine MBP. The ability to derive T cell lines and sublines from the spinal cords of mice with EAE should now aid in the elucidation of pathogenetic mechanisms in EAE by allowing for a characterization of those T cells found at the site of pathology.

T cell lines derived from the spinal cords of mice with experimental allergic encephalomyelitis are self reactive

Experimental allergic encephalomyelitis (EAE) is an animal model of T cell-mediated, central nervous system neuropathology that may be a relevant animal model for multiple sclerosis. EAE is usually induced by sensitization of animals with a xenogeneic myelin basic protein (MBP). Recently, MBP-reactive T cell lines and clones derived from lymphoid tissue of animals with EAE have proved very useful in elucidating certain aspects of the pathogenesis in EAE. However, questions relating to how T cells actually mediate the pathologic changes seen in EAE remain unresolved. We now report for the first time the derivation of long-term, interleukin 2-dependent T cell lines and sublines from a site of pathology in murine EAE--the spinal cord. All of the spinal cord-derived T cell lines and sublines were found to be "autoreactive" in that they responded to self (murine) MBP as well as to the xenogeneic immunogen, porcine MBP. The ability to derive T cell lines and sublines from the spinal cords of mice with EAE should now aid in the elucidation of pathogenetic mechanisms in EAE by allowing for a characterization of those T cells found at the site of pathology.