Progranulin expression in breast cancer with different intrinsic subtypes

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Progranulin (PGRN) is an 88-kDa glycoprotein implicated in tumorigenesis.
• High PGRN expression correlates with increased angiogenesis markers (VEGF, microvessel density) in breast carcinoma.
• No prior studies have correlated PGRN expression with clinicopathological features across intrinsic breast cancer subtypes.

Purpose of the Study:

• To investigate PGRN expression profiles in intrinsic breast carcinoma subtypes.
• To assess the relevance of PGRN expression to histopathological and clinicopathological features.
• To explore PGRN as a potential therapeutic target, particularly in triple-negative breast cancer (TNBC).

Main Methods:

• Immunohistochemical staining for PGRN, VEGF, and CD105 on 264 breast carcinoma tissue blocks (2006-2009).
• Classification of tumors into intrinsic subtypes.
• Analysis of PGRN expression correlation with histopathological and clinicopathological parameters, including node metastasis status (pN) and EGFR expression.

Main Results:

• PGRN expression showed no significant differences across intrinsic subtypes, but a trend towards higher expression was observed in TNBC.
• Excluding node-positive TNBC (pN(+)) revealed significant differences in PGRN expression across subtypes (p<0.01).
• In node-negative TNBC (pN(-)), strong PGRN expression significantly correlated with positive EGFR expression (p<0.01) and was associated with higher angiogenesis markers.

Conclusions:

• PGRN expression is not significantly different across all intrinsic breast cancer subtypes but shows a notable association in specific subgroups, especially node-negative TNBC.
• PGRN is a promising therapeutic target for node-negative TNBC, particularly given its correlation with EGFR.
• The interplay between PGRN, EGFR, and angiogenesis markers (VEGF/CD105) may drive angiogenesis in node-negative TNBC.