AIM: To explore the inhibitory effect of Ras-association domain family 1A ( RASSF1A) on the small-cell lung cancer cell growth .METHODS:The lentiviral expression vector containing RASSF1A gene was constructed and used to infect the small-cell lung cell line H446.The growth curve and cell cycle were detected by MTT assay and flow cytometry.The mRNA and protein levels of cell cycle-associated proteins were determined by real-time PCR and Western blotting.RESULTS:We obtained the H446 cells in which RASSF1A was stably expressed (named RASSF1A-H446). Compared with normal cell group and negative cell group , RASSF1A inhibited the proliferation of H446 cells, and arrested H446 cells in G1 phase.The expression of p21 and p27 was significantly increased , and E2F1 was significantly decreased in RASSF1A-H446 cells.CONCLUSION:RASSF1A inhibits the H446 cell growth by increasing the expressions of p 21 and p27, and decreasing the expression of E 2F1.