CTLA4 and neoplasm: Expression of PD‐L1, PD‐1 and CTLA‐4 mRNA was observed in pigmented and/or non‐pigmented atypical cells with vesicular nuclei and prominent nucleoli interpreted as tumour cells, as well as in non‐tumour cells, mostly characterised by scant cytoplasm, interpreted as small lymphocytes (Figure 1A,D,G).