Expression of autophagy-related proteins PTEN and MAP1LC3 in tongue squamous cell carcinoma

This study aims to evaluate the expression of autophagy-related protein cancer phosphatase and tensinhomology deleted on chromosome ten (PTEN) and microtubule-associated protein 1 light chain 3 (MAP1LC3) and investigate its significance in tongue squamous cell carcinoma (TSCC).

About 46 TSCC samples, 13 cases of precancerous lesion and 13 cases of adjacent tissues were enrolled. Immunohistochemistry were performed to examine the expression of PTEN, MAP1LC3. Statistical analyses were carried out to assess the associations among clinic pathologic parameters.

The positive expression rate of PTEN (34.78%) in TSCC was significantly lower than that in adjacent tissues (69.23%, X² = 4.926, P = 0.026) and precancerous lesions (76.92%, X² = 7.302, P = 0.007). The positive expression rate of MAP1LC3 (28.26%) in TSCC was significantly lower than that of adjacent tissues (61.53%, X² = 4.896, P = 0.027) and precancerous lesions (69.23%, X² = 7.275, P = 0.007), the difference was statistically significant. The expression of PTEN and MAP1LC3 was not correlated with age, sex, smoking, alcohol consumption and cell differentiation (P > 0.05). There was a significant difference in the expression of PTEN and MAP1LC3 in subgroup with different clinical stage and in subgroup with or without lymph node metastasis (P < 0.05). There is a significant difference in the tumor recurrence between PTEN protein expression positive subgroup and PTEN protein expression negative subgroup (X² = 4.629, P = 0.039), and there was no significant difference in the tumor recurrence between MAP1LC3 protein expression positive subgroup and MAP1LC3 protein expression negative subgroup (X² = 0.343, P = 0.453). There was a positive correlation between PTEN and MAP1LC3.

The expression of PTEN and MAP1LC3 suggested that autophagy associated proteins play a pivotal role in the progression, diagnosis and prognosis of TSCC. Down-regulation of PTEN and MAP1LC3 was observed in TSCC.