ALDH1A1 isozyme oxidizes Retinaldehyde to retinoic acid, which regulates the expression of the genes involved in tumor-initiating stem-like cells, thereby initiating tumor growth and resistance to drugs.

Much emphasis has been focused on ALDH1A1 as a CSC marker. High expression of ALDH1A1 has been reported as a poor prognostic marker in several tumor types and is associated with poor patient outcomes .

Breast cancer is one of the most common cancers among women. it is a heterogenous disease. several factors affect the prognosis of breast cancer. CSCs markers are one of the emerging prognostic biomarkers.

ALDH1A1 isozyme oxidizes Retinaldehyde to retinoic acid, which regulates the expression of the genes involved in tumor-initiating stem-like cells, thereby initiating tumor growth and resistance to drugs.

Much emphasis has been focused on ALDH1A1 as a CSC marker. High expression of ALDH1A1 has been reported as a poor prognostic marker in several tumor types and is associated with poor patient outcomes .

Inclusion Criteria:

• Patients with invasive mammary carcinoma carcinoma and underwent surgery

Exclusion Criteria:

• Cases received pre-operative chemotherapy or radiotherapy.
• Cases with insufficient clinical data.

sixty paraffin blocks of breast carcinoma collected from the archive of Pathology Department of Sohag Faculty of Medicine