TIA-1 positive tumor-infiltrating lymphocytes in nevi and melanomas

Tumor-infiltrating lymphocytes (TIL) have been shown to be an independent p rognostic factor in melanomas, To better characterize the host immune respo nse, we have classified TIL by their immunoreactivity against lymphoid mark ers in formalin-fixed, paraffin-embedded tissue. Monoclonal antibodies to l eukocyte common antigen (LCA) and TIA-1 (a granule-associated protein of cy totoxic T cells and NK cells) were used to immunostain a series of benign n evi, nontumorigenic radial growth phase, and tumorigenic vertical growth ph ase melanomas and metastases. Among nine nevi, few LCA(+) TIL were found, a mong which rare cells were positive for TIA-1 (mean, 2,0), Five nontumorige nic radial growth phase melanomas also had few total TIL and rare TIA-lf TI L (mean, 3.4); the nontumorigenic radial growth phase component of seven tu morigenic vertical growth phase melanomas had higher numbers of TIA-1(+) TI L, (mean, 11), Twelve cases of tumorigenic vertical growth phase melanoma s howed a variable but significantly greater number of both LCA+ TIL and TLA- lf TIL (mean, 30,6), Nine cases of metastatic melanoma had a wide range of variation in LCA as well as in TIA-1+ TIL (mean, 46). Although the mean tot al number of TIA(-1+) TIL increased from nontumorigenic radial growth phase to tumorigenic vertical growth phase to metastases, TIA-1(+) as a percenta ge of TIL declined across these categories of tumor progression (42%, 31%, and 26%, respectively). Our results show that these attributes of TLA-lf TI L, both increasing total number but decreasing percentage, appear to be a m arker of tumor progression of malignant melanomas. In addition, there was s ignificant variability in the number of TLA-1(+) TIL among advanced melanom as, raising the possibility that an assessment of TIA-lf TIL may prove a us eful prognostic tool for the evaluation of primary melanomas.