Association between increased αβ-crystallin (ABC) and abnormal LN332 (LN332) expression in triple negative (TNBC) and basal-like (BLBC) breast cancers has been suggested recently. This study aims to evaluate ABC and LN332 immunohistochemical expression in a series of TN infiltrating ductal breast carcinomas and its association with clinical-pathological features and prognostic significance.
Microarrays of 69 cases of TNBC cases were scored for the expression of ABC, LN332, CK5/6 and EGFR by immunohistochemistry with linked clinical and pathological data (age, tumor size, lymph node metastases, histological grade and subtype, lymphovascular invasion). Tumors were scored as strong, moderate and weakly positive for these biomarkers.
ABC was expressed in 72.7% (48/66) and LN332 in 63.8% (44/69) of cases. ABC immunostaining was predominantly cytoplasmic (73.5%) and LN332 was exclusively cytoplasmic (100%). ABC was expressed in 83% of BLBC, followed by the penta negative profile (17%). The 5-year survival was 0.67 and 0.75 for ABC negative and LN332 positive tumors, respectively. For the BLBC group this probability was 0.67, while in the penta negative group (ABC, LN332, CK5/6 and EGFR) it was only 0.37. ABC-/LN332+ profile was associated with longer probability of non-recurrence (10-years probability: 0.86 for ABC-/LN332+ tumors versus 0.36 for other profiles; P = 0.021) and longer cumulative survival (10-years probability: 1.0 for ABC-/LN332+ tumors versus 0.53 for other profiles; P = 0.031). There was no association between the ABC-negative/LN332-positive profile and BLBC.
ABC and LN332 are commonly expressed in TNBC, especially in BLBC. TNBC with ABC-/LN332+ profile showed better clinical outcome.