Fig. 1

A schematic diagram of the role of several miRNAs in triggering the PI3K/AKT signaling cascade in Cervical Cancer, LSCC and ESCC. Mounting studies have revealed that dysregulation of PI3K/AKT signaling pathway can play a crucial role in the carcinogenesis especially in squamous cell carcinomas. A recent study has detected that overexpression of miR-433 could suppress the growth and metastasis of cervical cancer cells via down-regulating the FAK/PI3K/AKT signaling cascade, and could enhance the apoptosis and caspase-3/-9 function. Moreover, miR-433 could promote the expression levels of p53 and Bax, and inhibit that of MDM2 in cervical cancer [18]. Further experiment has validated that miR-132 plays an oncogenic role in laryngeal squamous cell carcinoma by suppressing the expression of FOXO1, p27, and p21. Overexpression of this miRNA could promote cell proliferation and tumor growth via up-regulating cyclin D1 as well as activating the PI3K/AKT pathway in LSCC cells [34]. Another research has pointed out that miR-21 could have a significant role in enhancing cell proliferation, migration, invasion, and cell cycle, and suppressing apoptosis of human esophageal cancer cells via down-regulating the expression of PTEN and activating PI3K/AKT signaling pathway [47]. Green lines indicate the positive regulatory effect among miRNAs and their targets, and red lines depict negative ones among them. All information regarding the role of these miRNAs involved in the modulation of PI3K/AKT signaling cascade in various types of squamous cell carcinomas can be seen in Tables 1–4