Relationship betweenexpression of P-glycoprotein, GST- π and chemosensitivities inlymph node metastases of gastrointestinal carcinomas

：Objective To investigatethe relationship between expression of P-glycoprotein (P-gp), glutathione S-transferase-π (GST-π) and chemosensitivities inlymph node metastases (LNMs) of gastrointestinal carcinomas. Methods Tumorchemosesitivities to 9 drugs was measured by MTT assay, and the expression of P-gp and GST-π were determined immunohistochemically in primary tumor (PT) andLNMs of gastrointestinal carcinomas in 54 patients. Results The P-gp expression wasdetected in 22% cases (k= -0.0133, P =0.8698) for beth PT and LNMs, and of GST-π in 50% (k =0. 1137, P= 0. 1496). Expression of P-gp and GST-π in LNMs were stronger eompared with PT (Z = -3. 0448, Z = -2. 1178,both P <0. 05). The inhibition rates of LNMs cells for VCR, OPT, OXA, DDP and MTX werelower than those to PT (all P < 0. 05), but for VP-16 it was higher (P < 0. 05). InPT, there were negative correlation between expression of P-gp and inhibition rates oftumor cells for 5-FU, VCR and PTX respectively (r = -0. 4142 ～ -0. 5712, all P <0. 05), and GST-πfor 5-FU, VCR,OPT and PTX as well (r = -0. 3927 ～ -0. 4951, all P <0. 05).In LNMs, negative correlation between expression of P-gp and inhibition rates of tumorcells for VP-16, PTX and eADM were found statistically (r = - 0. 3802 ～ - 0. 4624, all P < 0. 05), and also GST-π for 5-FU, VCR and DDP (r = - 0. 3996 ～- 0. 5345, all P < 0. 05). Conclusions TheLNMs of gastrointestinal carcinomas are heterogeneous with respect to expression ofmdr-related factors and response to chemotherapy, and more resistant than the PT forchemotherapeutants. Effective adjuvant chemotherapy in gastrointestinal cancers depends ontargeting the metastatic component of the tumor. Key words: Gastrointestinal neoplasms;  Neoplasm metastases; P-glycoprotein;  Glutathione transferase;  Chemosensitivities