Currently no effective treatments for this regional-specific disease and the precise molecular mechanism involved remains unclear. Although some therapies including tumor removal surgery, radiotherapy, and chemotherapy have been developed, the survival rate has still not improved. Therefore, developing novel strategies for GSQCLC treatment is particularly important. Researchers have developed some anti-cancer drugs for this type of squamous cell lung carcinoma. Zhu and coworkers showed that phenylbutyrate could inhibit the proliferation of squamous cell lung carcinoma cells and induce tumor cell apoptosis. Chen et al. demonstrated that brain derived neuro-trophic factor enhanced YTMLC-90 cell growth. Our study for the first time investigated the regulatory mechanism between SB203580 miR-21 and its target genes, including PTEN, RECK and Bcl-2 in YTMLC-90 cells. Our goal is to identify novel potential therapeutic targets for this regional-specific squamous cell lung carcinoma based on the cellular and molecular level. It is well known that the abnormal expression of microRNAs is related to carcinogenesis. Numerous studies observed that overexpression of miR-155, miR-196a, miR-31, as well as miR-21 play an important role in progression of lung cancer. Moreover, the regulation of multiple target genes by miR-21 has been experimentally validated. PTEN and RECK are important regulators of multistep tumorigenesis in lung cancer and newly identified as direct targets of miR-21. Studies demonstrated that miR-21 down-regulates the expression level of tumor suppressor gene PTEN, which stimulates cell growth, invasion, and metastasis in NSCLC. It has been shown that miR-21 modulates cell growth, invasion, and apoptosis by targeting RECK in many cancers, such as oral cancer, esophageal cancer, prostate cancer, and glioma, however the relationship between miR-21 and RECK in lung cancer is largely unknown. In our study, we evaluated whether miR-21 participates in cell growth, proliferation, invasion, metastasis, and/or apoptosis via regulating PTEN and/or RECK in the regionally-specific lung cancer GSQCLC. As an oncogene, Bcl-2 is also a direct target of miR-21 and plays an important role in the tumor cell apopposis pathway. Previous data have shown that miR-21 targets Bcl-2 and participates in tumorigenesis of human glioblastoma, bladder cancer, and breast cancer. Our goal is to explore unclear molecular mechanisms between miR-21 and its targets in NSCLC cells and try to reveal the specificity and similarity of GSQCLC as compared to other NSCLC.