Isotropic 3D Nuclear Morphometry of Normal, Fibrocystic and Malignant Breast Epithelial Cells Reveals New Structural Alterations

Grading schemes for breast cancer diagnosis are predominantly based on pathologists' qualitative assessment of altered nuclear structure from 2D brightfield microscopy images. However, cells are three-dimensional (3D) objects with features that are inherently 3D and thus poorly characterized in 2D. Our goal is to quantitatively characterize nuclear structure in 3D, assess its variation with malignancy, and investigate whether such variation correlates with standard nuclear grading criteria.We applied micro-optical computed tomographic imaging and automated 3D nuclear morphometry to quantify and compare morphological variations between human cell lines derived from normal, benign fibrocystic or malignant breast epithelium. To reproduce the appearance and contrast in clinical cytopathology images, we stained cells with hematoxylin and eosin and obtained 3D images of 150 individual stained cells of each cell type at sub-micron, isotropic resolution. Applying volumetric image analyses, we computed 42 3D morphological and textural descriptors of cellular and nuclear structure.We observed four distinct nuclear shape categories, the predominant being a mushroom cap shape. Cell and nuclear volumes increased from normal to fibrocystic to metastatic type, but there was little difference in the volume ratio of nucleus to cytoplasm (N/C ratio) between the lines. Abnormal cell nuclei had more nucleoli, markedly higher density and clumpier chromatin organization compared to normal. Nuclei of non-tumorigenic, fibrocystic cells exhibited larger textural variations than metastatic cell nuclei. At p<0.0025 by ANOVA and Kruskal-Wallis tests, 90% of our computed descriptors statistically differentiated control from abnormal cell populations, but only 69% of these features statistically differentiated the fibrocystic from the metastatic cell populations.Our results provide a new perspective on nuclear structure variations associated with malignancy and point to the value of automated quantitative 3D nuclear morphometry as an objective tool to enable development of sensitive and specific nuclear grade classification in breast cancer diagnosis

Epigenetic events, remodelling enzymes and their relationship to chromatin organization in prostatic intraepithelial neoplasia and prostatic adenocarcinoma.

OBJECTIVE: To explore the nuclear chromatin phenotype, overall epigenetic mechanisms, chromatin remodelling enzymes and their role as diagnostic biomarkers in prostate lesions, using high-resolution computerized quantitative digital image analysis (DIA). MATERIALS AND METHODS: A tissue microarray (TMA) was constructed using paraffin wax-embedded prostatic tissues from 78 patients, containing 30 cores of benign prostatic hyperplasia (BPH), 10 of low-grade prostatic intraepithelial neoplasia (LGPIN), 38 of prostate adenocarcinoma, 20 of BPH tissue excised at 0.6-1 mm from LGPIN lesions, and 10 of BPH prostatic tissues obtained 0.6-1 mm from high-grade PIN (HGPIN) lesions. Chromatin phenotype was assessed on haematoxylin-stained sections using high-resolution texture analysis. For quantitative immunohistochemistry, antibodies raised against acetylated histone H3 lysine 9 (AcH3K9), 5'methylcytidine (5MeC) and the chromatin remodelling ATPase ISWI (SNF2H and SNF2L) were used. The immunodensity was measured using DIA to determine the epigenetic profile of the cases. At least 60 nuclei were measured from each case. RESULTS: There were many statistically significant differences in staining intensity and nuclear distribution patterns in chromatin phenotype and immunostaining (p </= 0.001). These changes allowed the differentiation between the various pathological subgroups with a classification accuracy of 76-100% using chromatin phenotype or immunostaining measuring epigenetic and chromatin remodelling changes (5MeC, AcH3K9 and ISWI). In PIN lesions, there was a high chromatin content with DNA-hypermethylation, while in prostatic adenocarcinoma there was a lower chromatin content with DNA-hypomethylation and H3K9-hypoacetylation. There was significantly more ISWI protein in neoplastic tissues. There were malignancy-associated changes (MAC) in chromatin phenotype and overall epigenetic events in BPH tissues adjacent to PIN lesions. CONCLUSIONS: The present study confirms the ability of high-resolution computerized digital imaging of nuclear texture features to detect changes in chromatin phenotype, epigenetic events and the presence of chromatin remodelling, factors that can be used to distinguish between different prostatic pathologies, i.e. BPH, LGPIN, HGPIN and prostate adenocarcinoma, and further allow the detection of MAC near PIN lesions. These results provide a base for future diagnostic applications of DIA combined with immunohistochemistry. Our experiments underscore the importance of epigenetic mechanisms during carcinogenesis. Further studies are needed to elucidate the complex interplay between chromatin structure, its modifications and the progression of prostate cancer