Identification of mRNAs expressed in tumor-infiltrating lymphocytes by a strategy for rapid and high throughput screening.

Most gene expression methods often involve cumbersome steps or use expensive facilities. Additionally, some of the techniques, such as cDNA biochip, cannot define the sub-population of tissue from which the amplified cDNA was made. Here we present a rapid and high throughput screening method for analyzing the pattern of gene expression of tumor-infiltrating lymphocyte (TIL), which can minimize manipulations in cloned DNA sequencing and in bioinformatics. The pattern of TIL gene expression was studied in one ovarian cancer and one liver cancer. Our results have demonstrated that TILs have three different gene expression profiles: the first set of genes is involved in cell proliferation and mitogenic stimulation, such as c-myc and IL-8, LD78, MIP-1beta, insulin-induced protein and AH-receptor; the second set of genes includes those involved in attachment of lymphocytes to endothelium and extravasation into tumor tissues such as P-selectin ligand and integrin; and the third set, which includes genes such as the perforin, FAS ligand and granzyme B, is related to cytotoxic function to tumor cells. The patterns of TIL gene expression obtained from two specimens are marginally different and can be used in explaining the basis of molecular mechanisms regulating cellular interactions and cytotoxicity.