KRAS and metastatic malignant neoplasm in the lymph nodes: To verify whether ACY1 expression was related to lymph node metastasis and cetuximab resistance in CRC, we selected 15 CRC patients and divided them into three groups: no lymph node metastasis, KRAS wild-type (Patients #1–#5, Group A); no lymph node metastasis, KRAS mutant-type (Patients #6–#10, Group B); and lymph node metastasis, KRAS mutant-type (Patients #11–#15, Group C).