Quantitative computerized image analysis of Tn and T (Thomsen-Friedenreich) epitopes in prognostication of human breast carcinoma

Glycosylation Alterations in Cancer Cells, Prognostic Value of Glycan Biomarkers and Their Potential as Novel Therapeutic Targets in Breast Cancer

Although we are lately witnessing major improvements in breast cancer treatment and patient outcomes, there is still a significant proportion of patients not receiving efficient therapy. More precisely, patients with triple-negative breast cancer or any type of metastatic disease. Currently available prognostic and therapeutic biomarkers are not always applicable and oftentimes lack precision. The science of glycans is a relatively new scientific approach to better characterize malignant transformation and tumor progression. In this review, we summarize the most important information about glycosylation characteristics in breast cancer cells and how different glycoproteins and enzymes involved in glycosylation could serve as more precise biomarkers, as well as new therapeutic targets.

Differentially Expressed Genes Associated With Prognosis in Locally Advanced Lymph Node-Negative Prostate Cancer

Older age is one of the main risk factors for cancer development. The incidence of prostate cancer, as a multifactorial disease, also depends upon demographic factors, race, and genetic predisposition. Prostate cancer most frequently occurs in men over 60 years of age, indicating a clear association between older age and disease onset. Carcinogenesis is followed by the deregulation of many genes, and some of these changes could serve as biomarkers for diagnosis, prognosis, prediction of drug therapy efficacy, as well as possible therapeutic targets. We have performed a bioinformatic analysis of a The Cancer Genome Atlas (TCGA) data and RNA-Seq profiling of a Russian patient cohort to reveal prognostic markers of locally advanced lymph node-negative prostate cancer (lymph node-negative LAPC). We also aimed to identify markers of the most common molecular subtype of prostate cancer carrying a fusion transcript TMPRSS2-ERG. We have found several genes that were differently expressed between the favorable and unfavorable prognosis groups and involved in the enriched KEGG pathways based on the TCGA (B4GALNT4, PTK6, and CHAT) and Russian patient cohort data (AKR1C1 and AKR1C3). Additionally, we revealed such genes for the TMPRSS2-ERG prostate cancer molecular subtype (B4GALNT4, ASRGL1, MYBPC1, RGS11, SLC6A14, GALNT13, and ST6GALNAC1). Obtained results contribute to a better understanding of the molecular mechanisms behind prostate cancer progression and could be used for further development of the LAPC prognosis marker panel.

MLS128 antibody-induced suppression of colon cancer cell growth is mediated by a desmocollin and a 110 kDa glycoprotein

Protein glycosylation is a diverse form of post-translational modification. Two to three consecutive O-linked N-acetylgalactosamines (Tn-antigens) are recognized by antibodies such as MLS128. MLS128 mAb inhibited cell growth and bound to a 110 kDa glycoprotein (GP) in LS180 and HT29 colon cancer cells. However, purification and identification of the 110 kDa GP was unsuccessful due to its low abundance. The present study used a highly sophisticated and sensitive mass spectrometry method to identify proteins immunoprecipitated with MLS128 and separated by two-dimensional gel electrophoresis. Three desmosome components were identified. Of these, desmocollin and desmoglein shared many similar characteristics, including molecular mass, pI, and potential Tn-antigen sites. Western blotting analyses of LS180 cell lysates revealed a common 110 kDa band recognized by MLS128 and anti-desmocollin, but not by anti-desmoglein. Immunofluorescence microscopy of LS180 cells revealed that desmocollin is membrane-bound, while desmoglein is primarily localized in the cytosol. Confocal microscopy demonstrated colocalization of the desmocollin-specific antibody with the MLS128 antibody on the cell membrane, suggesting that desmocollin may contain Tn-antigens recognized by MLS128. Treatment of LS180 cells with siRNA to knock down desmocollin expression or a desmocollin-specific antibody decreased cell viability, suggesting a critical role for this protein in cell growth and survival. N-glycosidase F digestion of the 110 kDa GP and desmocollin suggested that although both proteins contain N-glycosylation sites, they are not identical. These findings suggest that desmocollin colocalizes with the 110 kDa GP and that growth inhibition induced by the MLS128 antibody may be mediated through a mechanism that involves desmocollin.

Preclinical Analysis of JAA-F11, a Specific Anti-Thomsen-Friedenreich Antibody via Immunohistochemistry and In Vivo Imaging

The tumor specificity of JAA-F11, a novel monoclonal antibody specific for the Thomsen-Friedenreich cancer antigen (TF-Ag-alpha linked), has been comprehensively studied by in vitro immunohistochemical (IHC) staining of human tumor and normal tissue microarrays and in vivo biodistribution and imaging by micro-positron emission tomography imaging in breast and lung tumor models in mice. The IHC analysis detailed herein is the comprehensive biological analysis of the tumor specificity of JAA-F11 antibody performed as JAA-F11 is progressing towards preclinical safety testing and clinical trials. Wide tumor reactivity of JAA-F11, relative to the matched mouse IgG3 (control), was observed in 85% of 1269 cases of breast, lung, prostate, colon, bladder, and ovarian cancer. Staining on tissues from breast cancer cases was similar regardless of hormonal or Her2 status, and this is particularly important in finding a target on the currently untargetable triple-negative breast cancer subtype. Humanization of JAA-F11 was recently carried out as explained in a companion paper "Humanization of JAA-F11, a Highly Specific Anti-Thomsen-Friedenreich Pancarcinoma Antibody and In Vitro Efficacy Analysis" (Neoplasia 19: 716-733, 2017), and it was confirmed that humanization did not affect chemical specificity. IHC studies with humanized JAA-F11 showed similar binding to human breast tumor tissues. In vivo imaging and biodistribution studies in a mouse syngeneic breast cancer model and in a mouse-human xenograft lung cancer model with humanized 124I- JAA-F11 construct confirmed in vitro tumor reactivity and specificity. In conclusion, the tumor reactivity of JAA-F11 supports the continued development of JAA-F11 as a targeted cancer therapeutic for multiple cancers, including those with unmet need.

Mannosylated T/Tn with Freund's adjuvant induces cellular immunity

Inducing cancer-specific cellular immune responses has become an attractive strategy in cancer treatment. In this study, we investigated the role of several adjuvants in eliciting T/Tn-specific cellular immunity and protection against T/Tn expressing tumor challenge. T/Tn (9:1) antigen was purified from blood type “O” erythrocytes donated from healthy Korean volunteers. Immunization was performed using: T/Tn only, T/Tn mixed with Freund’s adjuvant (T/Tn + FA), keyhole limpet hemocyanin (KLH)-conjugated T/Tn mixed with FA (KLH-T/Tn + FA), and oxidized mannan-conjugated T/Tn mixed with FA (ox-M-T/Tn + FA). Mice immunized with ox-M-T/Tn + FA generated T/Tn-specific CD3, helper T (Th) cells, major histocompatibility complex (MHC) II, and MHC I; T/Tn presentation was significantly high and tolerogenic CD11b⁺ was the lowest among the tumor models. To verify Th type, we stained intracellular cytokines (interferon gamma (IFN-γ), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-4, and IL-10) using CD3 co-staining. Th1 (IFN-γ and GM-CSF) cytokines were highly expressed and showed high FasL/Fas ratios, cytotoxic T lymphocyte (CTL) activity, and cytotoxic T lymphocyte precursor (CTLp) activity in mice immunized with ox-M-T/Tn + FA. Lymphocyte infiltration was highest in mice immunized with ox-M-T/Tn + FA. Additionally, we monitored FasL, MHC I, CD301, and T/Tn expression levels using immunohistochemistry (IHC) on macrophage and tumor sites. The expression of all markers was highest in the ox-M-T/Tn + FA group. Furthermore, tumor retardation and survival rate were highest in the ox-M-T/Tn + FA group. These results demonstrate that a vaccine formulation of T/Tn conjugated with ox-M and mixed with FA-induced cellular immunity and sustained a humoral immune response without over-activating the immune system, thus effectively inhibiting tumor growth.

T/Tn immunotherapy avoiding immune deviation

Tumor immunotherapy, capable of inducing both cellular and humoral immune responses, is an attractive treatment strategy for cancer. It has been reported that the inactivation of cell-mediated immunity by hyper-activation of humoral immunity-referred to as immune deviation-does not inhibit tumor growth. We investigated the ability of several adjuvants to elicit Thomsen-Friedenreich (T/Tn)-specific humoral immunity while avoiding immune deviation and conferring protection against tumorigenesis. T/Tn (9:1) antigen was purified from blood type O erythrocytes donated by healthy Korean volunteers. Immunization was performed using T/Tn only, T/Tn mixed with Freund's adjuvant (T/Tn+FA), keyhole limpet hemocyanin (KLH)-conjugated T/Tn mixed with FA (KLH-T/Tn+FA), or oxidized mannan-conjugated T/Tn mixed with FA (ox-M-T/Tn+FA). Anti-T/Tn antibodies were generated in the T/Tn+FA, KLH-T/Tn+FA, and ox-M-T/Tn+FA groups. The antibody level was highest in the KLH-T/Tn+FA group. Mice immunized with ox-M-T/Tn+FA showed specific complement-dependent cytotoxicity, and were protected against T/Tn-positive mammary adenocarcinoma cell challenge, although anti-T/Tn antibody levels were the highest in the KLH-T/Tn+FA group. These results demonstrate that an ox-M-conjugated T/Tn vaccine mixed with FA can promote cellular immunity while moderating the humoral immune response, thereby effectively inhibiting tumor growth.

Tumor-associated glycans and their role in gynecological cancers: accelerating translational research by novel high-throughput approaches

Glycans are important partners in many biological processes, including carcinogenesis. The rapidly developing field of functional glycomics becomes one of the frontiers of biology and biomedicine. Aberrant glycosylation of proteins and lipids occurs commonly during malignant transformation and leads to the expression of specific tumor-associated glycans. The appearance of aberrant glycans on carcinoma cells is typically associated with grade, invasion, metastasis and overall poor prognosis. Cancer-associated carbohydrates are mostly located on the surface of cancer cells and are therefore potential diagnostic biomarkers. Currently, there is increasing interest in cancer-associated aberrant glycosylation, with growing numbers of characteristic cancer targets being detected every day. Breast and ovarian cancer are the most common and lethal malignancies in women, respectively, and potential glycan biomarkers hold promise for early detection and targeted therapies. However, the acceleration of research and comprehensive multi-target investigation of cancer-specific glycans could only be successfully achieved with the help of a combination of novel high-throughput glycomic approaches.

Aberrantly glycosylated MUC1 is expressed on the surface of breast cancer cells and a target for antibody-dependent cell-mediated cytotoxicity

Protein glycosylation often changes during cancer development, resulting in the expression of cancer-associated carbohydrate antigens. In particular mucins such as MUC1 are subject to these changes. We previously identified an immunodominant Tn-MUC1 (GalNAc-α-MUC1) cancer-specific epitope not covered by immunological tolerance in MUC1 humanized mice and man. The objective of this study was to determine if mouse antibodies to this Tn-MUC1 epitope induce antibody-dependent cellular cytotoxicity (ADCC) pivotal for their potential use in cancer immunotherapy. Binding affinity of mAb 5E5 directed to Tn-MUC1 was investigated using BiaCore. The availability of Tn-MUC1 on the surface of breast cancer cells was evaluated by immunohistochemistry, confocal microscopy, and flow cytometry, followed by in vitro assessment of antibody-dependent cellular cytotoxicity by mAb 5E5. Biacore analysis demonstrated high affinity binding (KD = 1.7 nM) of mAb 5E5 to its target, Tn-MUC1. Immunolabelling with mAb 5E5 revealed surface expression of the Tn-MUC1 epitope in breast cancer tissue and cell lines, and mAb 5E5 induced ADCC in two human breast cancer cell lines, MCF7 and T47D. Aberrantly glycosylated MUC1 is expressed on the surface of breast cancer cells and a target for antibody-dependent cell-mediated cytotoxicity suggesting that antibodies targeting glycopeptide epitopes on mucins are strong candidates for cancer-specific immunotherapies.

Tobacco mosaic virus as a new carrier for tumor associated carbohydrate antigens

Tumor-associated carbohydrate antigens (TACAs) are being actively studied as targets for antitumor vaccine development. One serious challenge was the low immunogenecity of these antigens. Herein, we report the results of using the tobacco mosaic virus (TMV) capsid as a promising carrier of a weakly immunogenic TACA, the monomeric Tn antigen. The copper(I) catalyzed azide-alkyne cycloaddition reaction was highly efficient in covalently linking Tn onto the TMV capsid without resorting to a large excess of the Tn antigen. The location of Tn attachment turned out to be important. Tn introduced at the N terminus of TMV was immunosilent, while that attached to tyrosine 139 elicited strong immune responses. Both Tn specific IgG and IgM antibodies were generated as determined by enzyme-linked immunosorbent assay and a glycan microarray screening study. The production of high titers of IgG antibodies suggested that the TMV platform contained the requisite epitopes for helper T cells and was able to induce antibody isotype switching. The antibodies exhibited strong reactivities toward Tn antigen displayed in its native environment, i.e., cancer cell surface, thus highlighting the potential of TMV as a promising TACA carrier.

pp-GalNAc-T13 induces high metastatic potential of murine Lewis lung cancer by generating trimeric Tn antigen

In order to analyze the mechanisms for cancer metastasis, high metastatic sublines (H7-A, H7-Lu, H7-O, C4-sc, and C4-ly) were obtained by repeated injection of mouse Lewis lung cancer sublines H7 and C4 into C57BL/6 mice. These sublines exhibited increased proliferation and invasion activity in vitro. Ganglioside profiles exhibited lower expression of GM1 in high metastatic sublines than the parent lines. Then, we established GM1-Si-1 and GM1-Si-2 by stable silencing of GM1 synthase in H7 cells. These GM1-knockdown clones exhibited increased proliferation and invasion. Then, we explored genes that markedly altered in the expression levels by DNA microarray in the combination of C4 vs. C4-ly or H7 vs. H7 (GM1-Si). Consequently, pp-GalNAc-T13 gene was identified as up-regulated genes in the high metastatic sublines. Stable transfection of pp-GalNAc-T13 cDNA into C4 (T13-TF) resulted in increased invasion and motility. Then, immunoblotting and flow cytometry using various antibodies and lectins were performed. Only anti-trimeric Tn antibody (mAb MLS128), showed increased expression levels of trimeric Tn antigen in T13-TF clones. Moreover, immunoprecipitation/immunoblotting was performed by mAb MLS128, leading to the identification of an 80 kDa band carrying trimeric Tn antigen, i.e. Syndecan-1. Stable silencing of endogenous pp-GalNAc-T13 in C4-sc (T13-KD) revealed that primary tumors generated by subcutaneous injection of T13-KD clones showed lower coalescence to fascia and peritoneum, and significantly reduced lung metastasis than control clones. These data suggested that high expression of pp-GalNAc-T13 gene generated trimeric Tn antigen on Syndecan-1, leading to the enhanced metastasis.

Cancer vaccines and carbohydrate epitopes

Tumor-associated carbohydrate antigens (TACA) result from the aberrant glycosylation that is seen with transformation to a tumor cell. The carbohydrate antigens that have been found to be tumor-associated include the mucin related Tn, Sialyl Tn, and Thomsen-Friedenreich antigens, the blood group Lewis related Lewis(Y), Sialyl Lewis(X) and Sialyl Lewis(A), and Lewis(X) (also known as stage-specific embryonic antigen-1, SSEA-1), the glycosphingolipids Globo H and stage-specific embryonic antigen-3 (SSEA-3), the sialic acid containing glycosphingolipids, the gangliosides GD2, GD3, GM2, fucosyl GM1, and Neu5GcGM3, and polysialic acid. Recent developments have furthered our understanding of the T-independent type II response that is seen in response to carbohydrate antigens. The selection of a vaccine target antigen is based on not only the presence of the antigen in a variety of tumor tissues but also on the role this antigen plays in tumor growth and metastasis. These roles for TACAs are being elucidated. Newly acquired knowledge in understanding the T-independent immune response and in understanding the key roles that carbohydrates play in metastasis are being applied in attempts to develop an effective vaccine response to TACAs. The role of each of the above mentioned carbohydrate antigens in cancer growth and metastasis and vaccine attempts using these antigens will be described.

Tumour-associated carbohydrate antigens in breast cancer

Glycosylation changes that occur in cancer often lead to the expression of tumour-associated carbohydrate antigens. In breast cancer, these antigens are usually associated with a poor prognosis and a reduced overall survival. Cellular models have shown the implication of these antigens in cell adhesion, migration, proliferation and tumour growth. The present review summarizes our current knowledge of glycosylation changes (structures, biosynthesis and occurrence) in breast cancer cell lines and primary tumours, and the consequences on disease progression and aggressiveness. The therapeutic strategies attempted to target tumour-associated carbohydrate antigens in breast cancer are also discussed.

Isolation and characterization of antibodies against three consecutive Tn-antigen clusters from a phage library displaying human single-chain variable fragments

The Tn-antigen, GalNAcalpha-Ser/Thr, is a tumour-associated carbohydrate antigen that may provide a sensitive and specific marker for pre-clinical detection of carcinoma and a target for cancer therapies. We recently reported that MLS128 monoclonal antibody treatment significantly inhibited colon and breast cancer cell growth. On the basis of our observations, the present study aimed to produce human anti-Tn-antigen antibodies with specificity similar to that of MLS128 monoclonal antibody, which recognizes a structure of three consecutive Tn-antigens (Tn3). Six phage clones displaying human single-chain variable fragments (scFvs) were isolated from a newly constructed phage library by panning and screening with a synthetic Tn3-peptide. Deduced amino-acid sequences of six anti-Tn3 scFvs exhibited a high degree of homology. Of those, anti-Tn3 4E10 and 4G2 scFv proteins were successfully purified from phage-infected Escherichia coli to near homogeneity. Surface plasmon resonance analyses revealed a K(D) of purified scFv proteins for Tn3 on an order of 10(-7) M, which is high for carbohydrate-specific monovalent antibodies. Further analyses suggested that both scFv proteins also bind to Tn2 and cultured colon and breast cancer cells. These results demonstrated the potential for use of these scFvs in developing antibody therapeutics targeting colon and breast cancer.

Tumor-associated Carbohydrate Antigens: Sialyl Lea and T/Tn Antigens in Canine Mammary Tumors

Twenty-eight canine mammary tubulopapillary carcinomas and 14 simple adenomas were studied by immunohistochemistry for the expressions of the tumor-associated carbohydrate antigens. Sialyl Lea was detected in 71.42% of the malignant and 92.84% of the benign tumors. Staining with anti-T and anti-Tn monoclonal antibodies revealed that 85.70% of the tubulopapillary carcinomas expressed T and Tn antigens. In contrast, 50% of the adenomas did not express T antigen, and 42.85% of them were only weakly stained for this carbohydrate structure. In the case of Tn antigen, the majority (57.14%) of samples was weakly stained, and no binding was observed in 35.71% of the analyzed specimens. Comparison of average values of reaction intensity (IRS) scale for malignant versus benign tumors by the Mann-Whitney U-test revealed a significant relationship between T and Tn antigens expression and type (malignant vs. benign) mammary tumors. Based on the results obtained, it is suggested that each of the studied antigens can be treated as a tumor-associated antigen of canine mammary tumors. However, only the T and Tn antigens seem to be associated with malignant transformation of mammary gland cells and to be of potential value as diagnostic markers.

MUC1 and the MUCs: A Family of Human Mucins with Impact in Cancer Biology

Mucins represent a family of glycoproteins characterized by repeat domains and a dense O-glycosylation. During the last two decades, the gene and peptide structures of various mucins as well as their glycosylation states were partly elucidated. Characteristic tumor-associated alterations of the expression patterns and glycosylation profiles were observed in biochemical, immunochemical, and histological studies and are discussed in the light of efforts to use the most prominent member in this family, MUC1, as a tumor target in anti-tumor strategies. Within this context the present review, focusing on MUC1, describes recent work on the regulation of mucin biosynthesis by cytokines and hormones, the role of mucins in cell adhesion, and their interaction with the immune system. Important aspects of clinical diagnostics based on mucin antigens are discussed, including the application of tumor serum assays and the significance of numerous studies revealing correlations between the expression of peptide cores or mucin-associated carbohydrates and clinicopathological parameters like tumor progression and prognosis.

Carbohydrate Array Analysis of Anti-Tn Antibodies and Lectins Reveals Unexpected Specificities: Implications for Diagnostic and Vaccine Development

The Tn antigen is a carbohydrate antigen expressed in most carcinomas, during embryogenesis, on pathogenic parasites, and on HIV. It has been evaluated extensively as a potential diagnostic marker and several Tn-based vaccines are in clinical trials. Based on discrepancies in the literature regarding Tn expression, we began to question whether antibodies and lectins used routinely to detect the Tn antigen were providing accurate information. To investigate this possibility, a carbohydrate microarray and a highly sensitive assay were developed and three frequently used Tn receptors (HBTn1, Bric111, and VVL-B4) were evaluated. Carbohydrate-array analysis revealed unexpected cross-reactivity with other human carbohydrate epitopes. VVL-B4 bound the Tn antigen, GalNAcalpha1-6Gal, and GalNAcalpha1-3Gal. Bric111 bound the Tn antigen, blood group A, GalNAcalpha1-6Gal, and GalNAcalpha1-3Gal. HBTn1 showed the best selectivity, but still displayed moderate binding to blood group A. Implications for the development of Tn-based diagnostics and vaccines are discussed.

Expression of peanut agglutinin-binding mucin-type glycoprotein in human esophageal squamous cell carcinoma as a marker

Background

The TF (Thomson – Friedenreich) blood group antigen behaves as an onco-foetal carcinoma-associated antigen, showing increased expression in malignancies and its detection and quantification can be used in serologic diagnosis mainly in adenocarcinomas. This study was undertaken to analyze the sera and tissue level detectable mucin-type glycoprotein (TF-antigen) by Peanut agglutinin (PNA) and its diagnostic index in serum as well tissues of human esophageal squamous cell carcinoma as marker.

Results

We examined 100 patients for serological analysis by Enzyme Linked Lectin Assay (ELISA) and demonstrated a sensitivity of 87.5%, specificity of 90% and a positive predictive value of 95%. The immuno-histochemical localization of TF antigen by Fluorescence Antigen Technique (FAT) in 25 specimens of normal esophageal squamous epithelium specimens and 92 specimens with different grades of, allowed a quicker and more precise identification of its increased expression and this did not correlate with gender and tumor size. There was a positive correlation between membrane bound TF antigen expression with different histological progression, from well differentiated to poorly differentiated, determined by PNA binding. Specimens showed morphological changes and a pronounced increase in PNA binding in Golgi apparatus, secretory granules of the cytosol of well differentiated and an increased cell membrane labeling in moderately and poorly differentiated, when compared with ESCC and normal tissues.

Conclusion

The authors propose that the expression of TF-antigen in human may play an important role during tumorigenesis establishing it as a chemically well-defined carcinoma-associated antigen. Identification of the circulating TF-antigen as a reactive form and as a cryptic form in the healthy individuals, using PNA-ELLA and Immunohistochemical analysis of TF antigen by FAT is positively correlated with the different histological grades as a simple and cost-effective method for the early diagnosis of ESCC. The present study reveals that, during tumorigenesis, an aberrant glycosylation takes place in Golgi apparatus leading to over secretion of TF antigen into the cytoplasm along with mucin granules and later into cell membrane. We suggest that the further characterization of TF antigen may unravel pathogenetic aspects of this silent disease.

Combinatorial evolution of high-affinity peptides that bind to the Thomsen-Friedenreich carcinoma antigen

Thomsen-Friedenreich (TF) antigen occurs on approximately 90% of human carcinomas, is likely involved in carcinoma cell homotypic aggregation, and has clinical value as a prognostic indicator and marker of metastasized cells. Previously, we isolated anti-TF antigen peptides from bacteriophage display libraries. These bound to TF antigen on carcinoma cells but were of low affinity and solubility. We hypothesized that peptide amino acid sequence changes would result in increased affinity and solubility, which would translate into improved carcinoma cell binding and increased inhibition of aggregation. The new peptides were more soluble and exhibited up to fivefold increase in affinity (Kd approximately equal to 60 nM). They bound cultured human breast and prostate carcinoma cells at low concentrations, whereas the earlier peptides did not. Moreover, the new peptides were potent inhibitors of homotypic aggregation. The maturated peptides will have expanded applications in basic studies of the TF antigen and particular utility as clinical carcinoma-targeting agents.

Quantitative study of breast cancer progression: different pathways for various in situ cancers

The chromatin pattern in nuclei from breast ductal proliferative lesions was quantitatively evaluated with the objective of deriving measures of tumor progression. A total of 110 cases were analyzed. There were 38 cases of normal tissue or benign proliferative lesions, 41 cases of ductal carcinoma in situ (DCIS), and 31 cases of microinfiltrating DCIS and of infiltrating cancer. A total of 9424 nuclei were analyzed. High-resolution images were digitally recorded. For each nucleus, 93 karyometric features descriptive of the spatial and statistical distribution of the nuclear chromatin were computed. Data analysis included establishing a profile of relative deviations of each feature from "normal," called the nuclear signature, and of lesion signatures as well as of trends of lesion progression. Two trends of evolution could be discerned: one from normal to hyperplasia, atypical hyperplasia, and comedo DCIS as representative of high-grade lesions; and the other from normal to hyperplasia to cribriform DCIS, solid DCIS, and infiltrating cancer, representing lower grade lesions. The nuclei in microinfiltrating foci are distinctly different from nuclei in high-grade comedo DCIS. The nuclei in microinfiltrating foci have a statistically significantly lower nuclear abnormality. They may represent outgrowing clones.