**Abstract**

Photodynamic Therapy (PDT) is a cancer treatment that used the interaction of a photosensitizing drug and a light source. PDT can lead to changes in the expression of various cellular elements, compromising cell adhesion, and cytoskeleton integrity in cells undergoing treatment. However, the pathways of cellular alterations caused by this treatment are little known. Alterations in expression in surface glycoproteins and glycolipids are significant features in malignant tumor transformation and are strongly associated with tumor cell adhesion, invasion, and metastasis. This study evaluated photodynamic therapy effects on indirect distribution surface glycoproteins in human laryngeal carcinoma HEp-2 cell line surface, using Click-iT™ Metabolic Glycoprotein Labeling Reagent. Aluminum Phthalocyanine Tetrasulfonate (AlPcS4) was administrated at 5 μM/mL, followed by one hour of the incubation period for its accumulation in the tumor cells. After this time, cultures were irradiated with LED (light-emitting diode) dispositive (BioPdi/IRRAD-LED) λ = 660 nm. Evaluation of glycoproteins was performed by flow cytometry. Knowledge of the cellular alterations caused by the treatment will allow obtaining tools for the potentiation or optimization and personalization of the anticancer treatment. This therapy has a low cost and better efficacy, when applied early, about radiotherapy chemotherapy.

**Keywords:** glycosylation, flow cytometry, cell culture, aluminum phthalocyanine tetrasulfonate
