Even though the fact that Let-7 miRNAs function as tumor suppressors[38–39] by suppressing oncogene ras, we did not notice significantly different expressions of kras, hras and nras in KS biopsies in our previous studies, implying the involvement of alternative mechanisms in the let-7 related regulation of latency-replication switch. This evidence concerns the gene NRAS and Kaposi's sarcoma.