Multidrug Resistance in Breast Cancer: From In Vitro Models to Clinical Studies

Table 4

Overview of clinical studies investigating the effect of ABC transporters.

Type of Study	No. of patients	Treatment	Detection Method	Outcome	Author
Neoadjuvant	21 patients	5-fluorouracil, epirubicin, cyclophosphamide and paclitaxel	RT-PCR	Differences seen in expression before treatment, no difference in expression response to treatment	[46]
Neoadjuvant	50	Cyclophosphamide, doxorubicin and 5-fluorouracil	Immunohistochemistry	Significant correlation between PGP expression prior to treatment and clinical response	[53]
Adjuvant	171	Chemotherapy +/− radiotherapy +/− hormonal therapy	RT-PCR	No significant correlation between PGP and MRP1 expression and survival	[48]
Adjuvant	85	Anthracycline based	RT-PCR	No significant influence of PGP or MRP1 expression on survival	[49]
Adjuvant	38	Doxorubicin	RT-PCR	No correlation between MRP1 expression and survival	[50]
Adjuvant	27	Chemoendocrine	RT-PCR	High expression levels of MRP1 increased risk of relapse. No significant difference in PGP expression	[54]
Adjuvant	1034	Cyclophosphamide, methotrexate and 5-fluorouracil or tamoxifen and goserelin	Immunohistochemistry	MRP1 expression predicts a shorter survival in patients treated with conventional chemotherapy	[55]
Adjuvant	59	Cyclophosphamide, methotrexate and 5-fluorouracil or 5-fluorouracil, doxorubicin/epirubicin and cyclophosphamide	RT-PCR	High PGP expression significant predictor of poor prognosis	[51]
Adjuvant	259	Cyclophosphamide, methotrexate and 5-fluorouracil	Immunohistochemistry	Increased expression of MRP1 associated with increase in relapse and number of deaths	[56]
Adjuvant	104	Radiotherapy +/− chemotherapy +/− hormonal therapy	Immunohistochemistry	High expression levels of PGP associated with shorter survival	[57]