Liu X, Song S, Shi C
Affiliated Hospital of Academy of Military Medical Sciences, Beijing.
Zhonghua Yi Xue Za Zhi. 1997 Jul;77(7):488-90.
To investigate the role of expression of multidrug resistance gene (mdr-1 gene) in chemotherapeutic resistance of breast cancer and to determine if expression of mdr-1 gene may act as an index for predicting chemotherapy response and prognosis.
Using reverse transcription-polymerase chain reaction (RT-PCR) technique, we determined the levels of mdr-1 mRNA in 82 breast cancer samples.
Positive expressions of mdr-1 gene were 34.3% in 35 cases of untreated primary breast cancer and 59.0% in 47 cases of relapsed metastatic breast cancer, separately, and the difference was statistically significant (P < 0.05). In 28 cases of relapsed metastatic breast cancer of mdr-1 gene positive expression, 22(78.6%) were ever treated with MDR related drugs. Levels of mdr-1 gene expression of all 7 cases were higher after chemotherapy than before chemotherapy. Positive expressions were 16.7% and high grade positive expressions were 5.6% in 18 sensitive cases. Positive expressions were 71.4% and high grade positive expressions were 50.0% in 14 resistant cases. The difference was statistically significant (P < 0.01). There were no relations between expression of mdr-1 gene and ages, menopause status, lymphnode involvements, clinical stages, and estrogen receptor levels.
The results indicated that retreated metastatic breast cancer is more extensively resistant than untreated primary breast cancer and acquired drug resistance is an important reason. Expression of mdr-1 gene seems to be a reference index for predicting response of chemotherapy.
探讨多药耐药基因（mdr-1基因）表达在乳腺癌化疗耐药中的作用，并确定mdr-1基因表达是否可作为预测化疗反应及预后的指标。
采用逆转录聚合酶链反应（RT-PCR）技术，测定82例乳腺癌样本中mdr-1 mRNA水平。
35例未经治疗的原发性乳腺癌中mdr-1基因阳性表达率为34.3%，47例复发性转移性乳腺癌中为59.0%，差异有统计学意义（P<0.05）。在28例mdr-1基因阳性表达的复发性转移性乳腺癌中，22例（78.6%）曾接受过与多药耐药相关的药物治疗。所有7例化疗后mdr-1基因表达水平均高于化疗前。18例敏感病例中阳性表达率为16.7%，高等级阳性表达率为5.6%。14例耐药病例中阳性表达率为71.4%，高等级阳性表达率为50.0%，差异有统计学意义（P<0.01）。mdr-1基因表达与年龄、绝经状态、淋巴结受累情况、临床分期及雌激素受体水平无关。
结果表明，复发性转移性乳腺癌比未经治疗的原发性乳腺癌具有更广泛的耐药性，获得性耐药是一个重要原因。mdr-1基因表达似乎是预测化疗反应的一个参考指标。
