Phosphatidylinositol Glycan Anchor Biosynthesis Class U Protein in Breast Cancer

Breast cancer (BC) is the most common cancer among females. It is known to be the second leading cause of cancer-related deaths among women worldwide . Although the incidence rates of breast cancer vary between developed and developing nations, it continues to be the most prevalent form of cancer among women in Egypt, with an estimated mortality rate of approximately 11% in 2020 . Breast cancer is a heterogeneous disease, so treatment and prognosis vary based on tumor pathological type, histological grade, lymph node involvement, hormone receptor status and disease stage * however even patients with similar prognostic features can experience different clinical outcomes after treatment . Despite significant advancements in early screening and diagnostic techniques, the incidence of breast cancer continues to rise annually, accounting for approximately 11.7% of all newly diagnosed cancer cases. So detection of new prognostic indicators is critical for selecting the optimal treatment modalities, evaluating the response and creating a follow-up plan to improve clinical outcome . Phosphatidylinositol glycan anchor biosynthesis class U (PIGU), also known as cell division cycle 91-like 1 (CDC91L1), is an important subunit of glycosylphosphatidylinositol transaminase (GPI-T) complex. It has been reported that the over-activity of certain components of the GPI T complex contributes to the development of various cancers, such as breast cancer, bladder cancer, lymphoma, and non-small cell lung cancer. Studies have shown that PIGU has the potential to be a prognostic biomarker and therapeutic target for liver cancer, ovarian cancer and colorectal cancer . Also, PIGU expression levels have been associated with radiotherapy for differentiated thyroid cancer and the risk of cutaneous melanoma. It has been demonstrated that PIGU promotes hepatocellular carcinoma (HCC) progression via increasing HCC cell viability, migration, invasion and inhibiting apoptosis by activating the transcription factor nuclear factor-kappa B (NF-κB) pathway . Recent researches verify that PIGU protein levels were significantly higher in breast cancer patients compared to normal people . So it was speculated that PIGU is playing an important role in tumor development, progression and it can be considered as a marker for breast cancer screening and prognosis (12).