EGFR gene expression-suppressing siRNA, precursor of same, and applications thereof

A precursor sequence, wherein the sequence has a structure from the 5′ terminus to the 3′ terminus as shown in formula I:

• wherein
• B1 is a first ribonucleic acid sequence comprising an EGFR siRNA sense strand sequence;
• B2 is a sequence substantially or completely complementary to B1, and B2 is not complementary to C, wherein substantially complementary means there are 2-8 non-complementary bases between B2 and B1;
• C is a stem-loop structure sequence;
• and
• A1 is UGCUG and/or A2 is CAGG or CAGGA,
• wherein, the nucleotide sequence of the EGFR siRNA sense strand is selected from the group consisting of:
• SEQ ID NO:
• 197, SEQ ID NO:
• 17, SEQ ID NO:
• 20, SEQ ID NO:
• 35, SEQ ID NO:
• 42, SEQ ID NO:
• 47, SEQ ID NO:
• 52, SEQ ID NO:
• 59, SEQ ID NO:
• 63, SEQ ID NO:
• 68 and SEQ ID NO:
• 72;
• and the precursor sequence as shown can be processed in a host to form the EGFR siRNA.