We read with great interest the recent publication by Matsuo et al1 and the accompanying editorial by Goldenring and Mills.2 We agree with the authors that the Runx1 enhancer element, eR1, marks among other cell types a stem cell population within the gastric isthmus. Gastric stem cells reside within the corpus isthmus and supply progeny bidirectionally toward the top and base of glands.3,4 Findings in the paper1 confirm previous studies by our group that first demonstrated an isthmus corpus stem cell marked by Mist1.