title: Isotropic 3D nuclear morphometry of normal, fibrocystic and malignant breast epithelial cells reveals new structural alterations.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona, United States of America.
authors.forename: Vivek
authors.initials: V
authors.lastname: Nandakumar
authors.forename: Laimonas
authors.initials: L
authors.lastname: Kelbauskas
authors.forename: Kathryn F
authors.initials: KF
authors.lastname: Hernandez
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Lintecum
authors.forename: Patti
authors.initials: P
authors.lastname: Senechal
authors.forename: Kimberly J
authors.initials: KJ
authors.lastname: Bussey
authors.forename: Paul C W
authors.initials: PC
authors.lastname: Davies
authors.forename: Roger H
authors.initials: RH
authors.lastname: Johnson
authors.forename: Deirdre R
authors.initials: DR
authors.lastname: Meldrum
mesh_terms: D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000473:pathology*; D002460:Cell Line; D002467:Cell Nucleus / Q000473:pathology; D004847:Epithelial Cells / Q000473:pathology*; D005260:Female; D005348:Fibrocystic Breast Disease / Q000473:pathology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009362:Neoplasm Metastasis