The fluoresceinated HSA-miR-LET-7c probe has been designed from mature human miR-LET-7c sequence. This HSA-miR-LET-7c identifies miR-LET-7c sequences in formalin-fixed, paraffin-embedded human tissues and freshly prepared frozen tissues by in situ hybridization. This probe does not react with normal human mRNA or nuclear DNA present in tissues.