To explore the biomarker distribution of human oral cancer samples from different people and different body parts, while amplifying the signals of the target proteins, the biomarkers inside the tissue were labeled with the enzyme HRP. Figure illustrates the mechanism of SECM imaging of the oral cancer biomarkers. The rehydrated formaldehyde-fixed tissue was treated with the primary and secondary HRP conjugated antibodies. The secondary HRP conjugated antibody on the tissue section catalyzed the oxidation of FcMeOH to FcMeOH + in the presence of H2O2. We used the sample generation/ tip collection (SG/TC) mode and applied a constant voltage of -0.2 V at the ultramicroelectrode. The FcMeOH + in the solution was reduced to FcMeOH on the electrode surface. Therefore, the more target molecules, the higher the current value was measured, and SECM could map the areas overexpressed areas. After labeling IL-6 proteins, pretreated oral tissue samples from the tongue, mandible, and submandibular glands were scanned in the x direction with a soft gold probe. Figure displays the SECM x line scan of the tissue array containing normal tissue, stage I, II, and III oral cancer tissues. The current value was proportional to the quantity of biomarkers and thus reflected the IL-6 distribution. The literature indicated that interleukin 6 (IL-6) is a potential biomarker for the oral cavity and oropharyngeal squamous cell carcinoma. In figure 1d, the higher current value (more negative) over the stage III oral cancer tissue of the lower jaw indicated higher levels of IL-6 protein, while the current value of stage III oral cancer in the submandibular gland was slightly higher than that of normal tissue. To explore more facts about IL-6 distribution and compare the stability of the novel gold ultramicroelectrode, we also investigated more SECM images and x line scans by carbon soft stylus microelectrode used in the previous study (figure ). The sensitivity and quality of SECM images or line scans performed by the commercial soft carbon stylus electrode and newly developed electrode were similar. The results of line scan experiments were comparable.