Experimental data indicate that miR-21 also plays a crucial role in tumor cell proliferation, apoptosis, and invasion, consistent with miR-21's ability to repress important tumor suppressors such as PTEN (50), PDCD4 (56), TPM-1 (60), Tap-63 (61), SPRY2 (62), and hMSH2 (63). Here, PDCD4 is linked to neoplasm.