POSTN and neoplasm: Previous studies reported low POSTN expression in most tumor-derived cell lines, whatever their origin [4,7,9,13,18,19,21] but most cancer cell lines tested had been established a long time before and subjected to extensive culture, making it difficult to establish whether the decreased expression in cancer cell lines was reflecting a loss of stromal-associated POSTN expression as suggested by some authors [10,16,17,22] or artifacts due to prolonged cell culture.