s ([Figure. 0](#pone-0000000-g000){ref-type="fig"}).  ![Mean value comparison of subepithelial and deep tryptase positive mast cells in healthy controls, different stages of OSF, and OSCC.](pone.0000000.g000){#pone-0000000-g000}  Deep distribution of chymase positive MCs in healthy controls, different stages of OSF and OSCC group ([Figure. 00](#pone-0000000-g000){ref-type="fig"}) {#s0e} --------------------------------------------------------------------------------------------------------------------------------------------------------  ![Deep distribution of 