Relationship of HMEC as determined by transcriptional profiles. A. Data from 2319 genes were used to determine the number of principal components of the data. Three components were identified, and the contribution of the components to the transcription profile of each cell line samples are shown in the figure. Individual replicates for each cell line are shown. Cell lines grouped in Figure 1 are shown in Figure 2A as shown in the legend. Vertical axis is PC1, the first, and therefore the strongest. principal component. B. Unsupervised clustering of HMEC. All genes that change expression in one or more samples were used to cluster the cell types and lines by overall similarity. Cell types and lines are identified by color under the designations: pre-stasis HMEC: light green; post-selection HMEC: light blue; fully immortalized HMEC: dark blue; p53-/- fully immortal HMEC: burgundy, and lines not formally characterized: black. Samples of 184A1 and 184B5 designated by (a) were obtained from ATCC.