## Description

Expression data from "Systematic variation in gene expression patterns in human cancer cell lines" [pubmed], Ross et al., Nature Genetics 2000 Mar; 24(3):227-35. cDNA microarrays were used to explore the variation in expression of approximately 8,000 unique genes among the 60 cell lines used in the National Cancer Institute's screen for anti-cancer drugs. The authors have provided a web supplement where more data and experimental description can be obtained. cDNA probes were placed on the draft human genome using genebank sequences referenced by the IMAGE clone ids.

The data are shown in a tabular format in which each column of colored boxes represents the variation in transcript levels for a given cDNA across all of the array experiments, and each row represents the measured transcript levels for all genes in a single sample. The variation in transcript levels for each gene is represented by a color scale, in which red indicates an increase in transcript levels, and green indicates a decrease in transcript levels, relative to the reference sample. The saturation of the color corresponds to the magnitude of transcript variation. A black color indicates an undetectable change in expression, while a gray box indicates missing data.

## Display Options

This track has filter options to customize tissue types presented and the color of the display.

Combine Arrays: This option is only valid when the track is displayed in full. It determines how the experiments are displayed. The options are:

- Arrays Grouped by Tissue Median: (default) Displays the median of the log ratio scores of all cell lines from the different tissue types.
- Arrays Grouped by Tissue Mean: Displays the mean of the log ratio scores of all cell lines from the different tissue types.
- All Arrays (experiments): Displays the log ratio score for all cell line experiments.

Color Scheme: Data are presented using two color false display. By default the Brown/Botstein colors of red -> positive log ratio, green -> negative log ratio are used. However, a yellow/blue option can be selected for those who are colorblind.

## Details Page

On the details page, the probes presented correspond to those contained in the window range displayed on the Genome Browser. The exon probe and experiment selected are highlighted in blue.