^(99m)Tc-MIBI断层显像用于肺癌p-糖蛋白定性检测的临床研究

Clinical study of 99m Tc MIBI SPECT imaging for detection of multidrug resistant p glycoprotein expression in lung cancer

目的初步探讨９９ｍＴｃ甲氧基异丁基异腈（ＭＩＢＩ）断层显像用于肺癌ｐ糖蛋白（ｐＧＰ）定性检测的可行性。方法采用二时相断层显像，以横断面病灶处９９ｍＴｃＭＩＢＩ的储留指数（ＲＩ）为ｐＧＰ定性指标，以ＲＩ＜０为ｐＧＰ阳性的界值进行ｐＧＰ定性。按ＷＨＯ推荐的分级标准将疗效分为完全或部分缓解（ＣＲ或ＰＲ）及无效（ＮＲ）两组，然后将ｐＧＰ定性结果与疗效进行比较。结果７１例Ⅲ～Ⅳ期肺癌患者原发灶中３５个病灶为ｐＧＰ阳性，其中２９个疗效为ＮＲ，阳性符合率为８２９％；另３６个病灶为ｐＧＰ阴性，其中疗效为ＣＲ（ＰＲ）者２４例，阴性符合率为６６７％。与免疫组化法和ＰＣＲ技术相比，可避免取材受限及ｐＧＰ非均一表达等因素影响。

Purpose Multidrug resistance (MDR) of tumor to cytotoxic drugs is a common cause for failure of chemotherapy in the majority of cancer patients One of the mechanisms of MDR is due to drug efflux driven by p glycoprotein (p GP) expressed on the membrane of tumor cells The aim of the present study was to develop a method of functional imaging with 99m Tc MIBI to detect the drug efflux mediated by p GP in lesions of lung cancer Methods Before chemotherapy, 99m Tc MIBI imaging was performed on each patient with a two phase protocol (30 and 120 minutes postinjection) in a tomographic mode Retention indices (RIs) of 99m Tc MIBI at tumor sites were calculated from counts at the lesion sites and the negative value of RI was defined as p GP positive According to criteria proposed by the WHO, therapeutic tumor response was scored as no response (NR), partial regression (PR) or complete regression (CR) after 3 courses of chemotherapy Then, the significance of this technique was assessed Results In total, 71 original lesions of lung cancer patients (staged as Ⅲ b～Ⅳ) were included in this study 35 lesions were p GP(+) and 36 lesions were p GP(-) by MIBI imaging 29 (82 9%) lesions in the p GP(+) group had a therapeutic score of NR, while 24 lesions (66 7%) in p GP(-) were scored as CR or PR The accuracy of this method was 74 6%(53/71) Conclusions Several invasive methods such as immunohistochemical staining and PCR have been developed to detect p GP in tissue Compared with biopsy, which was subject to sampling errors and heterogeneity of p GP expression, the present technique was a non invasive and independent from sampling errors Therefore, it might serve as an effective complement to the other techniques to detect p GP mediated MDR