We use mi RNA array using 4k fixed probes. miRNA is small RNA composed of about 25 nucleotides and controls mRNAs. More than ten thausands of human miRNAs were found. miRNA targets
multiple mRNAs.
Cancers are consiered to be caused by various mechanisms. Roughly tumor promoting and inhibiting factors are not balanced but shifted. Immunity is generally decreased and
cannot kill the cancer ccells.