Immunohistochemical analysis of cancer stem cell markers in invasive breast carcinoma and associated ductal carcinoma in situ: relationships with markers of tumor hypoxia and microvascularity.

We performed immunohistochemical analysis of 3 cancer stem cell-related markers (CD44(+)/CD24(-/low), aldehyde dehydrogenase [ALDH]-1, CD133) in 94 invasive ductal carcinomas and assessed relationships with markers of hypoxia (carbonic anhydrase IX [CAIX]), tumor microvessel density (CD31), and clinicopathologic variables. Overall, 10% of tumors were CD44(+)/CD24(-/low), 13% were ALDH-1(+), 25% were CD133(+), 35% were immunonegative, and 1 tumor was immunopositive for all 3 markers. Associated ductal carcinoma in situ (DCIS) was present in 48% of tumors. Marker immunopositivity was detected in DCIS in 13% (CD44(+)/CD24(-/low)), 7% (ALDH-1(+)), and 32% (CD133(+)) of these tumors and was more likely present in DCIS when also detected in the invasive compartment (P = .03, P = .001, and P = .009, respectively). CD44(+)/CD24(-/low) cells were more common in progesterone receptor-negative tumors (P < .01), and ALDH-1(+) cells were more common in estrogen receptor-negative tumors (P < .01). CD133(+) cells were more common in patients younger than 50 years (P < .05) and in high grade (P < .01), localized (P < .05), and estrogen receptor-negative (P < .001), progesterone receptor-negative (P = .02), and triple-negative breast cancers (P < .001). CD44(+)/CD24(-/low) (P = .06) and CD133(+) (P = .02) tumor cells were more common in CAIX(+) versus CAIX(-) tumors, whereas ALDH-1(+) tumors had a higher mean microvessel density than did ALDH-1(-) tumors (P = .002). No significant relationships were observed between the markers studied and survival for 5 years. Our study demonstrated the presence of cancer stem cell marker-positive tumor cells in DCIS as well as invasive breast cancer and showed that CD44(+)/CD24(-/low) and CD133(+) cells were more frequently observed in hypoxic regions of tumor, whereas ALDH-1(+) cells more commonly colocalized to tumors with high microvessel density.