NRAS and breast cancer: To further investigate whether the integrated N-Ras/ERK/PI3K/NFκB/Lin28b signaling pathway was essential for the repression of miR98 by CCL18, we transfected siRNAs targeting N-Ras or Lin28b mRNA into MCF-7 breast cancer cells, which were then exposed to CCL18 (20 ng/ml) for 48 hr.