Seven of nine NPC tumors had lower CLDN11 expression levels (Fig. 2e, T<N #1–7 and Additional file 4: Figure S2) compared with their normal counterparts; by contrast, two NPC tumors (Fig. 2e, T=N #8–9 and Additional file 4: Figure S2) had similar CLDN11 expression compared with the adjacent normal tissues. Here, CLDN11 is linked to nasopharyngeal carcinoma.