Thousands of long intergenic non-protein coding RNAs (lincRNAs) have been identified in mammals in genome-wide sequencing studies. Some of these RNAs have been consistently conserved during the evolution of species and could presumably function in important biologic processes. Therefore, we measured the levels of 26 highly conserved lincRNAs in a total of 176 pairs of endometrial carcinoma (EC) and surrounding non-tumor tissues of two distinct Chinese populations. Here, we report that a lincRNA, LINC00672, which possesses an ultra-conserved region, is aberrantly down-regulated during the development of EC. Nevertheless, LINC00672 is a p53-targeting lincRNA acting along with heterogeneous nuclear ribonucleoproteins as a suppressive cofactor, which locally reinforces p53-mediated suppression of LASP1, an evolutionarily conserved neighboring gene of LINC00672 and putatively associated with increased tumor aggressiveness, during anti-tumor processes. LINC00672 overexpression could lower the levels of LASP1 and slow the development of malignant phenotypes of EC both in vitro and in vivo. Moreover, LINC00672 significantly increased the 50% inhibitory concentration of paclitaxel in EC cells and increased the sensitivity of xenograft mice to paclitaxel. These findings indicate that LINC00672 can influence LASP1 expression as a locus-restricted cofactor for p53-mediated gene suppression, thus impacting EC malignancies and chemosensitivity to paclitaxel.