The present study aims to evaluate the serum level of FGF-21 in patients with breast cancer and its correlation with clinical, laboratory, and pathological data.

Breast cancer is the most common malignant tumor in women, accounting for about 30 %, and its mortality rate is15 % of the incidence rate.

Studies in recent years have shown that the incidence of breast cancer is increasing year by year, which seriously affects Women's quality of life.

Several hormonal. metabolic and inflammatory mechanisms are known to play a role in the development and progression of breast cancer.

Fibroblast growth factor 21 (FGF21) is a protein produced mainly in the liver and regulated by diseases.The elucidation of the endocrine FGF21 signaling pathways in the control of metabolic disease, peroxisome proliferator-activated receptor-α (PPAR-α) which functions in lipid metabolism. However, more data support a versatile role for this molecule acting as a physiologic alert system in several energy homeostasis and their complications has raised great interest and hope in the last year.

Cancer-associated fibroblasts are activated fibroblasts that serve as a key component of the tumor receptors. FGFR1 is often overexpressed in breast and lung cancer, Promoter hypermethylation correlates microenvironment; FGF-19, FGF-21 and FGF-23 are endocrine FGFs that bind to Klotho and FGF with poorer survival of patients.

Clearly, further studies are needed to elucidate the mechanisms behind the increased serum FGF21 levels a high FGF21 secretion by the liver and also by the tumor cells or the stress caused by microenvironment condition that induces an increased FGF21 secretion by mainly the hepatocytes or/and adipocytes in less in cancer patients. It is believed that the elevated FGF21 levels observed in these patients could be due to metabolic disorders. Alternatively, the initiation of the tumor itself could be considered as a stressful degree. A study shows that Circulating FGF-21 level is associated with increased risk of early and late stages of (11)Another study shows that FGF21 is useful as a diagnostic as well as prognostic factor in patients with colorectal carcinogenesis ,supporting a role of inflammation and metabolism atall stages of colorectal carcinogenesis, and suggesting potential use of this biomarker for risk stratification in CRCscreening. endometrioid endometrial carcinoma.

The role of FGF21 in breast cancer and its level is not adequatelyincluded however a study byRanuncolo etal., revealed increased serum level as well astissue expression level of FGF21 in breast cancer.

Inclusion Criteria:Female patients admitted at south Egypt cancer institute who diagnosed as breast cancer basedon full clinical, radiological and pathological assays.

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Exclusion Criteria:Patients diagnosed with other concomitant cancers.

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Female patients admitted at south Egypt cancer institute who diagnosed as breast cancer basedon full clinical, radiological and pathological assays. b. Exclusion criteria: