C‐ MYC and IGF‐II mRNA‐binding protein (CRD‐BP/IMP‐1) in benign and malignant mesenchymal tumors

Mouse coding region determinant–binding (mCRD‐BP) and human IGF‐II mRNA–binding 1 (hIMP‐1) proteins are orthologous mRNA‐binding proteins that recognize c‐ myc and IGF‐II mRNA, respectively, and regulate their expression posttranscriptionally. Here, we confirm that human CRD‐BP/IMP‐1 binds to c‐ myc mRNA and that it is predominantly expressed in fetal tissues. Moreover, hCRD‐BP/IMP‐1 expression was detected in cell lines of neoplastic origin and in selected primary tumors. In a series of 33 malignant and 10 benign mesenchymal tumors, 73% and 40%, respectively, were found to express hCRD‐BP/IMP‐1. In particular, expression was significant in 14 Ewing's sarcomas, all of which were positive. The data suggest that hCRD‐BP/IMP‐1 plays a role in abnormal cell proliferation in mesenchymal tumors. © 2001 Wiley‐Liss, Inc.