MMP1 and gastric cancer: MLK3 appears to function as an oncogene to promote cell migration and invasion through the MLK3/JNK pathway in human breast and gastric cancer cells (7, 8, 10), the MLK3/FRA-1/MMP-1 axis in human triple-negative breast cancer cells (28), or MLK3/ERK signaling in ovarian and colorectal cancer cells (9, 11).