Figure 1.

(A): Cluster mean characteristics expressed as a ratio to the population means. Data from the six-color analysis was subjected to k-means clustering and principal component analysis using JMP-7 (SAS Institute, Research Triangle, NC, http://www.sas.com). For each cell, six fluorescence intensity measurements as well as forward- and side-scatter data were utilized. For each cell line, at least two staining/analysis runs were included in the analysis. Cluster characteristics are tabulated as ratio of the cluster mean to the overall average. Thus, ratios > 1 indicate values higher than the overall average and ratios < 1 indicate lower values. Color coding: green >1.5; gray 1.5–0.7; red <0.7. (B): Cluster pattern of breast, prostate, ovarian, colon, and lung cancer cell lines. Data were analyzed using k-means clustering, and the resulting clusters were color-coded. Plots were generated using the first two principal components and grouped by tumor type. Correlation between cluster patterns was analyzed for each tumor type using JMP-7. Breast cancer cell lines are organized to illustrate the partitioning of stem cell marker co-expression with the molecular taxonomy of breast cancer. Cell lines BT549, HS578T, and MDA-MB-231 fall into the “normal-like” category; cell lines MCF-7 and T47 are “luminal type”, and MDA-MB-468 is “basal type”.