الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Worldwide BC represents the most common type of cancers.In Egypt BC represents a serious public health problem. It constitutes 38% of all newly diagnosed cancer cases among Egyptians.
Despite knowing the high-risk populations for BC development, the lack of sensitive and specific biomarkers hinders early detection of the disease at a curable stage. Therefore, the identification of new diagnostic markers for BC becomes a top priority.
lncRNAs may act as “oncogenes” or “tumor suppressors” for cancers. Among lncRNAs, MALAT1 has a relationship with cancers.
The present study was meant to validate the role of serum MALAT1 expression as diagnostic and prognostic marker for BC and to assess the possible relation of serum selenium concentration and MALAT1 expression in Egyptian female patients.
In order to achieve this goal, 40 BC patients (group I) were included in the study and were divided into two subgroups;
• group IA consisted of 20 patients with early (non-metastatic) BC
• group IB consisted of 20 patients with late (metastatic) BC. The study
also included 10 healthy subjects as controls (group II).
The following investigations were performed for all patients and healthy subjects:
BC tumor markers including CEA and CA15.3 were measured using commercially available ELISA kit.
Total RNA was extracted from serum samples followed by reverse transcription and then real time PCR for MALAT1. The comparative cycle threshold (Ct) approach was used to calculate Relative expression of serum MALAT1. (2–ΔΔCt).
Serum selenium levels were measured using atomic absorption spectrophotometry.
Statistical analysis of the studied parameters showed the following results:
The level of CEA and CA15.3 were statistically significantly higher in patients with late stages (metastatic group) of BC, early stages (non-metastatic group) of BC compared to healthy subjects. CEA and CA15.3 were also significantly higher in patients with late stages of BC than patients with early stages of BC.
The relative expression of serum MALAT1 was statistically significantly higher in patients with late stages and early stages BC compared to healthy subjects. In addition, it was significantly higher in patients with early stages BC than late stages.
The sensitivity and specificity of serum CEA, CA15.3 and serum MALAT1 expression levels as markers for the diagnosis of BC have been determined by plotting a receiver-operating characteristic (ROC) curve.
At the cut-off value of >1.1, the sensitivity of serum CEA in detecting BC has been estimated to be 92.5% while its specificity has been shown to be 90%.
The diagnostic performance of serum MALAT1 relative expression to detect BC from normal was done using ROC curve and it showed that MALAT1 had a sensitivity of 77.5% and a specificity of 90%.
Combined together, serum CEA (cut off value = >1.58) and serum MALAT1 expression (cut off value = >1.10) had a sensitivity of 97% and a specificity of 90%.
In addition, the diagnostic performance of serum MALAT1 relative expression to diagnose early BC was performed by ROC curve that showed that the sensitivity of serum MALAT1 in detecting early BC has been estimated to be 95% while its specificity has been shown to be 90%.
In addition, the level of serum selenium was statistically significantly lower in BC patients compared to healthy subjects. Selenium level was also significantly lower in patients with late stages of BC than patients with early stages of BC.
There was a significant positive correlation between serum MALAT1 expression and selenium in metastatic BC patients.
from the current study we concluded that serum MALAT1 relative expression could be novel biomarkers in diagnosis of early stages of BC. When combined together, CEA and MALAT1 levels showed better sensitivity and specificity in BC diagnosis. Also, their serum expression is significantly associated with tumor stage.