Immunohistochemical analysis of NY-ESO-1 antigen expression in normal and malignant human tissues

NY-ESO-I, a member of the CT (cancer/testis) family of antigens, is express ed in normal testis and in a range of human tumor types. Knowledge of NY-ES O-I expression has depended on RT-PCR detection of mRNA and there is a need for detecting NY-ESO-I at the protein level. In the present study, a metho d for the immunochemical detection of NY-ESO-I in paraffin-embedded tissues has been developed and used to define the expression pattern of NY-ESO-I i n normal tissues and in a panel of human tumors, No normal tissue other tha n testis showed NY-ESO-I reactivity, and expression in testis was restricte d to germ cells particularly spermatogonia, In human tumors, the frequency of NY-ESO-I antigen expression corresponds with past analysis of NY-ESO-I m RNA expression e.g.. 20-30% of lung cancers, bladder cancers and melanoma, and no expression in colon and renal cancer. Go-typing of NY-ESO-I antigen and mRNA expression in a large panel of lung cancers showed a good correlat ion, There is great variability in NY-ESO-I expression in individual tumors , ranging from an infrequent homogeneous pattern of staining to highly hete rogeneous antigen expression. (C) 2001 Wiley-Liss, Inc.