Low MLL2 Protein Expression Is Associated With Fibrosis in Early Stage Gastric Cancer

Abstract

Background/aim: Myeloid/lymphoid or mixed lineage leukemia 2 (MLL2) gene is mutated in gastric cancer, with most resulting in inactivated proteins. In this study, we examined the expression of MLL2 protein in gastric cancers.

Patients and methods: The expression of MLL2 protein in cancer cell nuclei was studied by immunohistochemistry in tissue microarrays of 529 human gastric cancers. MLL2 expression was classified into low and high expression from the point of zygosity, and its relationships with mismatch repair protein expression and clinicopathological features were examined.

Results: Low expression of MLL2 was associated with younger age, MSH6, and early cancers. MLL2-low pT1a cancers were associated with fibrosis, especially ulcer scars, and in 62.5% of them there was no direct contact between carcinoma and fibrosis.

Conclusion: There is potentially an association between low expression of MLL2 protein and gastric malignancy from chronic fibrosis.

Keywords: Gastric cancer; MLL2 (KMT2D); fibrosis; immunohistochemistry; ulcer scar.