ARID1A and neoplasm: Furthermore, the chance for a spatial barcode in a biopsy holding a tumour-associated mutation to fall in the inflammation resistant epithelial cluster 0 is the lowest out of all epithelial cluster except for the healthy cluster 3 (Fig. 4c), To determine whether the inflammation-resistant environment of cluster 0 could promote expansion of non-oncogenic clones, we used immunostaining to detect variation in expression of the Arid1a gene.