Low-density lipoprotein receptor–related protein 1 is associated with proliferation and invasiveness in Her-2/neu and triple-negative breast carcinomas

SummaryLow-density lipoprotein receptor–related protein 1, a member of the low-density lipoprotein cholesterol receptor family, has been implicated in the progression of certain tumors; but it remains unclear whether it plays a role in infiltrating ductal breast carcinomas. We studied a series of 81 ductal breast tumors to determine the correlation of low-density lipoprotein receptor–related protein 1 overexpression with clinicopathologic and immunohistochemical characteristics associated with prognosis. Low-density lipoprotein receptor–related protein 1 overexpression was identified in 14% (11/81) of tumors and was correlated with a high nuclear grade (P = .043), high mitotic index (P = .006), and Ki-67 greater than 20% (P = .047). Furthermore, low-density lipoprotein receptor–related protein 1 expression was associated with aggressive carcinomas (triple-negative tumors [21%, 7/33] and Her-2/neu tumors [17%, 4/24]) but not with hormone-dependent carcinomas (0%, 0/24) (P = .040). There was no correlation between low-density lipoprotein receptor–related protein 1 expression and survival, but a trend was found between low-density lipoprotein receptor–related protein 1 overexpression and tumor recurrence. Low-density lipoprotein receptor–related protein 1 overexpression was related to proliferation and invasiveness in Her-2/neu and triple-negative breast carcinoma. Moreover, patients with low-density lipoprotein receptor–related protein 1–positive tumors had higher cholesterol levels (62.5%, 5/8) than those with low-density lipoprotein receptor–related protein 1–negative tumors (40%, 19/47). Nevertheless, the correlation between low-density lipoprotein receptor–related protein 1 and hypercholesterolemia was not statistically significant; but cholesterol levels were higher in patients with triple-negative breast carcinoma (60%, 15/25) and Her-2/neu carcinomas (40%, 6/15) than in luminal-A carcinomas (20%, 3/15) (P = .046). These findings suggest a relationship between hypercholesterolemia and aggressiveness of ductal breast carcinomas.