GABBR1 and malignant colon neoplasm: However, irrespective of whether expression of GABAA or GABAB receptor subunits were altered in colon cancer, expression of particular receptor subtypes (GABRA1, GABRA5, GABRD, GABRE, GABRG1, GABRG3, GABBR1, and GABBR2) was significantly associated with poor clinical outcome (Table 1).