MDR1T-129C, but not G2677A,T and C3435T, was associated with the lower expression of MDR1 mRNA both in colorectal adenocarcinomas (p=0.040) and adjacent noncancerous colorectal tissues (p=0.023), possibly being an useful invasive marker predicting poorly-differentiated colorectal adenocarcinomas and thereby the poor prognosis of the patients, especially when no extra biopsy samples will be obtained.
To evaluate chemosensitivity and its correlation with expression levels of the multidrug resistant transporter (MDR1) and the multidrug resistance-associated proteins 1 and 2 (MRP1, MRP2) mRNA in human colorectal adenocarcinomas.
Fifteen percent (13/87) of the tumors were positive for the MDR1 gene, but the level was low in all samples except in one adenocarcinoma which expressed a high level of MDR1.
We examined the levels of expression of the multidrug resistance-associated protein (MRP) gene quantified by Northern blot analysis in comparison with those of the MDR1 gene determined by reverse transcription-polymerase chain reaction (RT-PCR) in 104 non-small-cell lung cancer (NSCLC) specimens [59 adenocarcinoma (Ad), 40 squamous cell carcinoma (Sq), four large cell carcinoma (La) and one adeno-squamous carcinoma (AdSq)].
We have attempted to reverse the MDR phenotype by treating human adenocarcinoma resistant cells with 20 mers of synthetic unmodified oligodeoxynucleotide MDR1 antisenses.
Using the DNA fragment from normal tissues rather than KB cells, we have reanalyzed MDR1 mRNA levels in 12 renal carcinomas and 4 colon adenocarcinomas.
We have found that normal human kidney, six of eight adenocarcinomas of the kidney, and four cell lines derived from kidney adenocarcinomas express high levels of mdr1 mRNA.