Lastly, the cancerous and normal biopsies incubated with either uninhibited or inhibited AF350-WGA resulted in greater fluorescence than the control tumor sample that was not incubated with any AF350-WGA. This demonstrates that the
observed fluorescence from tissue stained with the lectin conjugate is not a result of intrinsic tissue autofluorescence at the excitation wavelength of 365nm. Histological analysis revealed that 4/7 patients Lumacaftor chemical structure had stage I cancer, 1/7 had stage II cancer, and 2/7 had stage IV cancer. Of the seven patients, 6/7 exhibited squamous cell carcinoma while 1/7 exhibited dysplasia. All normal biopsies were confirmed to be free from disease. The histological results are summarized in Table 3. Histology pictures for the tissue in Figure 2 can be seen in Figure 3. Here normal tissue was histologically verified (Figure 3A), whereas cancerous tissue was verified as stage I squamous cell carcinoma ( Figure 3B). It should be noted that the effect of AF350 and AF647 ABT-199 lectin binding on H&E staining was tested by comparing lectin labeled slices with unlabeled control slices from the same biopsy set. Comparison of these slices showed no effect of lectin labeling on H&E staining (data not shown). Furthermore, H&E staining was identical for normal and clinically abnormal tissue independent of the degree of staining with Alexa
Fluor lectin conjugates. The use of molecular and biochemical changes as a basis to develop early detection methods of oral cancer second were explored in this manuscript. The lectin WGA was primarily chosen for this application as it has high affinity for sialic acid and N-acetyl glucosamine residues which are known to be overexpressed in neoplastic tissue due to aberrant glycosylation , , ,  and . Furthermore, the relative expression of these sialic acid residues in the
epithelium is suggested to be representative of tumor prognosis ,  and . The data presented here demonstrate that WGA fluorophore probes can agglomerate on cancer cells overexpressing these glycomolecules, successfully yielding statistically higher fluorescence in cancerous tissue than normal tissue. Additionally, the WGA fluorophore probes resulted in a higher SNR than tissue UV autofluorescence at 365nm. Furthermore, through inhibitory binding studies with WGA it was shown that the lectin binding is molecularly specific to these glycans since inhibited WGA resulted in decreased tissue fluorescence, highlighting that the WGA is in fact binding to cellular glycans overexpressed in cancerous tissues. Lastly, this experiment showed that fluorescence intensity differences are not due to tissue diffusion variations between normal and tumor tissues (i.e. leaking vasculature or compromised mucosa). Our data demonstrate that the use of WGA fluorophore probes is a significant improvement over current autofluorescent methods.