TPO and thyroid nodule: HBME1, CK19, CD26/DPPIV, TPO and c-met have also been reported to be useful markers for improving the preoperative characterisation of thyroid nodules (De Micco et al, 1994, 1999; Ruco et al, 2001; Aratake et al, 2002; Rosai, 2003; Maruta et al, 2004; Mechanick, 2004; Weber et al, 2004; Papotti et al, 2005; Prasad et al, 2005; Saggiorato et al, 2005; de Matos et al, 2005).