Changes in aldehyde dehydrogenase-1 expression during neoadjuvant chemotherapy predict outcome in locally advanced breast cancer

Table 5 Summary of major studies investigating the clinical significance of ALDH1 in locally advance breast cancer

Study	Chemotherapy	No	Antibody	ALDH1 cutoff	% positive	Main results
Tanie et al. 2009[26]	Paclitaxel → FEC	108	BD	≥5%	19	• ALDH1(+) but not CD44+/CD24- phenotype is associated with chemoresistance
Gong et al. 2010[27]	FEC	192	Abcam	≥20%	19.8	• ALDH1 at baseline correlated with clinical response (CR/PR) and OS
Sakakibara et al. 2011[28]	AC → paclitaxel	115	BD	≥5%	39	• ALDH1(+) cells in residual axillary nodes is associated with poor prognosis
Lee et al. 2011[29]	AD or AC	92	BD	≥5%	13	• ALDH1(+) but not ALDH1(−) cases had high pCR
Lee et al. 2011[29]	AD or AC	92	BD	≥5%	13	• Increase in ALDH1 after NAC is associated with poor DFS
Resetkova et al. 2009[30]	Anthracycline/paclitaxel	34	BD	Any	56	• Stromal but not the tumor expression of ALDH1 is prognostic in breast cancer.
Current study	FEC → TAX Or TAX → FEC	119	BD	≥5%	47	• Pre NAC, ALDH1(+) is associated with poor pCR rates
						• Post NAC, ALDH1(+) cells in residual primary tumor is prognostic
						• Degree of chemoresistance may be different for different chemotherapy types

There was consistency among most of the studies in terms of the primary antibody used and cut-off point utilization. Variation in results could be explained by the differences in study designs and/or patients’ population.
AC, adriamycin (doxorubicin), cyclophosphamide; DFS, disease free survival; FEC, fluorouracil, epirubicin, cyclophosphamide; NAC, neoadjuvant chemotherapy; OS, overall survival; TAX, docetaxel.

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