MUC5AC and chronic rhinosinusitis with nasal polyps: The use of funnel plots, along with Begg's and Egger's tests, for investigating publication bias revealed no significant publication bias in the analysis of MUC5AC expression for CRSwNP patients (p = 1.000 and p = 0.558 according to Begg's and Egger's tests, respectively; Figure 5A), CRSsNP patients (p = 0.308 and p = 0.148 according to Begg's and Egger's tests, respectively; Figure 5B), and IHC positive area analysis for CRSsNP patients (p = 0.764 and p = 0.456 according to Begg's and Egger's tests, respectively; Figure 5C).