SLC4A1 and lung carcinoma: Interestingly, the cytokeratin AE1/AE3-stained xMD-procured lung carcinoma cells showed a 13-fold increase in KRAS mutation frequency (%) in comparison to the macrodissected heterogeneous cytospin (67.4% vs. 4.9%) and a 15-fold increase in the STK11 mutation frequency (%) (45.4% vs. 2.9%) (Fig 4B).