To determine whether p16INK4A immunopositive senescent cells were thyroid tumour cells or stromal cells, we assessed the expression of BRAFV600E using VE1, a BRAFV600E-specific monoclonal antibody and thyroid transcription factor-1 (TTF-1) in formalin-fixed paraffin embedded (FFPE) tissues of BRAFV600E-expressing PTC. Here, TTF1 is linked to thyroid tumor.