Most current studies focus on the role of HtrA1 in tumor development and progression through analysis of its expression as mRNA [11, 12, 17, 34–36, 39–41] or protein [9, 10, 13, 15, 17, 35–38], probably because proteins are more varied than DNA or RNA and therefore carry more information than nucleic acids. This evidence concerns the gene HTRA1 and neoplasm.