Abstract: Objective: To detect the expression of prohibitins 2 in cutaneous squamous cell carcinoma, Bowen's disease and actinic keratosis, and to evaluate the effect of prohibitins 2 knockout on the proliferation of cutaneous squamous cell carcinoma cell line A431. Methods: The expression of prohibitins 2 in 40 cases of cutaneous squamous cell carcinoma, 18 cases of Bowen's disease, 17 cases of actinic keratosis and 9 cases of normal skin tissue were detected by immunohistochemistry. Prohibitins 2 knockout A431 cells were generated by CRISPR/Cas9 technology and the knockout effect was confirmed by Western blot. The effect on cell proliferation was measured by CCK8 and cell clone formation experiment. Additionally, the phosphorylation level of AKT at Ser473 was semiquantitatively analyzed by Western blot. Results: The nuclear expression of prohibitins 2 in cutaneous squamous cell carcinoma (90.00%), Bowen's disease (66.70%) and actinic keratosis (41.18%) was higher than that in normal skin tissue (0.00%)（Ps<0.05）, and the expression of prohibitins 2 in cutaneous squamous cell carcinoma was higher than that in actinic keratosis (P<0.05）.The expression rates of prohibitins 2 in cutaneous squamous cell carcinoma, Bowen's disease, actinic keratosis and normal skin tissue were decreased gradually and there was a significant difference among these 4 groups (P<0.01). There was no significant difference of the expression of prohibitins 2 in different sex, age, location, course of disease, tumor diameter, depth of invasion, differentiation, Broder grade (Ps>0.05). The expression of prohibitins 2, the cell viability, the numbers of clone formation in two prohibitins 2 knockout groups  were lower than that in control group, with significant differences (Ps<0.05). The expression of p-AKT was significantly down-regulated with the decrease of prohibitins 2 expression level (P<0.05). Conclusion: The expression of prohibitins 2 may promote the occurrence of cutaneous squamous cell carcinoma, and its mechanism may be related to the activation of oncogene AKT.

Key words: prohibitins 2, cutaneous squamous cell carcinoma, cell proliferation, AKT