Further analysis of the moderate-intensity area within the overall HER2 low-expressing tumor showed a significantly lower Raman signal intensity (outlined in light blue in Figure 3C, Raman spectrum in light blue in Figure 3F) when compared to a high-intensity area within the high-expressing HER2 tumor (outlined in yellow in Figure 3C, Raman spectrum in yellow in Figure 3F). Here, ERBB2 is linked to neoplasm.