GPER1 and cancer: used 57 fresh tumor tissues sample from 29 patients to quantify the overexpression of four cancer biomarkers, including HER2, membrane estrogen receptor (mER), EGFR, and CD44, by locally applying targeted SERS NPs at the same time (Figure 19B).[135] The results demonstrated that REMI could quickly detect positive surgical margins (< 15 min), with a specificity and sensitivity of 92.1% and 89.3%, respectively.