PTPN11 and neoplasm: In many cancers, called immunologically “cold” tumours, the suppression of the microenvironment can be shaped by CD-33-related Siglecs that generate signals via the immunoreceptor tyrosine-based inhibitory motif (ITIM)-coupled with tyrosine–protein phosphatase non-receptor type 6 (SHP-1) and tyrosine-protein phosphatase non-receptor Type 11 (SHP-2) molecules [16,17].