Complement component 1, q subcomponent binding protein is a marker for proliferation in breast cancer

Area of Science:

• Oncology
• Molecular Biology

Background:

• Complement component 1, q subcomponent binding protein (C1QBP) exhibits elevated mRNA expression in breast cancer tissues.
• C1QBP is a multi-compartmental protein implicated in various cellular functions.

Purpose of the Study:

• To investigate the association between C1QBP protein expression in breast cancer tissue microarrays (TMAs) and clinicopathological parameters, particularly tumor size.
• To validate the TMA findings through an in vitro study involving C1QBP inhibition in breast cancer cells.

Main Methods:

• Immunohistochemical analysis of C1QBP and proliferating cell nuclear antigen (PCNA) on breast cancer TMAs from invasive ductal carcinoma patients.
• In vitro study using T47D cells (progesterone receptor-positive) with C1QBP siRNA transfection, followed by gene and protein expression analysis (RT-PCR, Western blot) and cell proliferation assays.

Main Results:

• C1QBP protein was detected in 131/132 samples, predominantly in the cytoplasm.
• Higher C1QBP expression was significantly associated with older patients and increased tumor size (P<0.01).
• C1QBP independently predicted tumor size in progesterone-positive tumors and correlated with PCNA expression. C1QBP down-regulation reduced T47D cell proliferation.

Conclusions:

• C1QBP protein expression is linked to clinicopathological features, including tumor size, in breast cancer.
• C1QBP plays a role in breast cancer cell proliferation.
• C1QBP may serve as a potential proliferative marker in breast cancer, especially in progesterone-positive subtypes.