Effect of HOTAIR knockdown on tumor growth in vivo . (A) Tumor growth curves were measured after injection of BGC-823 cells transfected with sh-HOTAIR or pENTR vector. Tumor volume was calculated every 3 days. Data are presented as mean ± s.d. (n = 5). (B) Tumor weight. Values are means of tumor weight ± s.d. (C) qRT-PCR analysis of HOTAIR expression in tissues of resected tumors. (D) Tumors developed from BGC-823/sh-HOTAIR cells showed a lower level of PCNA protein than tumors developed from BGC-823/pENTR vector cells. Upper: H & E staining; Lower: immunostaining. *P < 0.05 and **P < 0.01.