We apologize for an error that we just found in the paper published online on 21 February 2018. The 1st row/1st column of Figure 8G (PITA Normal) was inadvertently duplicated from 2nd row/1st column of Figure 8I (PISA Adjacent colonic mucosa). The 2nd row/1st column of Figure 8G (PISA Normal) was inadvertently duplicated from 2nd row/2nd column of Figure 8G (PISA Distal colonic mucosa). A corrected version of Figure 8G is provided below. No conclusion was affected by this error, but we apologize for not detecting it before publication and any inconvenience caused.