# Expression of Cyclin D1 and Claudin-1 in Invasive Breast Carcinoma and Their Correlation with Clinicopathological Parameters

## TL;DR

This study examines how cyclin D1 and claudin-1 protein levels in breast cancer tissues relate to patient outcomes and tumor characteristics.

## Contribution

The study identifies cyclin D1 as a potential prognostic marker and suggests claudin-1's role in breast cancer subtypes.

## Key findings

- Cyclin D1 expression is significantly linked to nodal status and luminal-type breast cancer.
- Claudin-1 is expressed in both luminal and HER2/neu-positive tumors but shows no strong correlations.
- Cyclin D1 positivity may indicate better prognostic factors in breast cancer patients.

## Abstract

Evidence-based medicine has shown that patients with similar risk factors, stages, and therapy often have different clinical outcomes, highlighting the heterogeneity of breast cancer. In a quest for a better, cost-effective approach, researchers proposed the selection of surrogate IHC markers such as cyclin D1 and claudin-1 for the prognosis of breast cancer patients, supplementing the traditional ER, PR, and HER2/neu receptor.

This retrospective study was conducted in a tertiary care hospital in northern India and included 50 cases of invasive breast carcinoma obtained from mastectomies, wide local excisions, and biopsies diagnosed over 4 years. In addition to ER, PR, and Her2/neu, claudin-1 and cyclin D1 IHC expression was assessed.

Cyclin D1 expression exhibited a statistically significant correlation with nodal status involvement (P=0.011) and with luminal-type breast carcinoma (P=0.023). Though there was no significant statistical correlation between claudin-1 and various clinic pathological features, it was seen to be positive in both luminal and HER2/neu-positive tumors.

Our findings advocated the expression of IHC namely, cyclin D1 and claudin-1, in cases of breast cancer. Cyclin D1 positivity may show a significant association with better prognostic determinants while claudin-1 negative tumors may tend to be more often triple negative. Thus, IHC can be used in resource-constraint settings to substitute expensive molecular techniques.