SSTR2 and neoplasm: Investigating the correlation of SST2 immunohistochemical scoring versus PET scans of [68 Ga]Ga-DOTATATE tracer in GEP-NET patients, Yu et al.34 found that the highest sensitivity and specificity of IRS in predicting the imaging results were obtained when defining the positivity cutoff value as 6, meaning that 51–80% of the tumor cells should be moderately stained or 10–50% should be strongly stained.