\HeaderA{leukemia}{Gene expression data from Golub et al. (1999)}{leukemia}
\keyword{datasets}{leukemia}
\begin{Description}\relax
Gene expression data (3051 genes and 38 tumor mRNA samples) from the
leukemia microarray study of Golub et al. (1999).
\end{Description}
\begin{Usage}
\begin{verbatim}
data(leukemia)
\end{verbatim}
\end{Usage}
\begin{Details}\relax
\end{Details}
\begin{Value}
A list with the following elements:
\begin{ldescription}
\item[\code{X}] a (38 x 3051) matrix giving the expression levels of 3051 
genes for 38 leukemia patients. Each row corresponds to a patient, each column to a
gene.
\item[\code{Y}] a numeric vector of length 38 giving the cancer class of each
patient.
\item[\code{gene.names}] a matrix containing the names of the 3051 genes for the gene
expression matrix \code{X}. The three columns correspond to
the gene 'index', 'ID', and 'Name', respectively.

\end{ldescription}
\end{Value}
\begin{Source}\relax
The dataset was taken from
the R package multtest. The data are described in Golub et al. (1999) and can be freely
downloaded from \url{http://www-genome.wi.mit.edu/MPR/}.
\end{Source}
\begin{References}\relax
S. Dudoit, J. Fridlyand and T. P. Speed (2002). Comparison of discrimination
methods for the classification of tumors using gene expression data, Journal of
the American Statistical Association \bold{97}, 77--87.  

Golub et al. (1999). Molecular classification of cancer: class discovery
and class prediction by gene expression monitoring, Science \bold{286},
531--537.
\end{References}
\begin{Examples}
\begin{ExampleCode}
# load plsgenomics library
library(plsgenomics)

# load data set
data(leukemia)

# how many samples and how many genes ?
dim(leukemia$X)

# how many samples of class 1 and 2, respectively ?
sum(leukemia$Y==1)
sum(leukemia$Y==2)\end{ExampleCode}
\end{Examples}

