Abstract:
P-Element-induced wimpy testis (PIWI) proteins are engaged in epigenetic regulation of gene expression
in germline cells when they are in combination with PIWI-interacting RNA (piRNA). Different types of
tumour cells have been found to exhibit abnormal expression of piRNA and PIWI proteins. HCC is majorly
diagnosed in later stages, which is associated with lower survival rates. There is an urgent need for
improved, more specific and less invasive diagnostic methods that can detect earlier stages of the
disease. Purpose: The aim of this study was to assess the diagnostic potential by determining the
expression profiles of PIWI-like protein-1, -2, -3, & -4 (PIWIL1, PIWIL2, PIWIL3, & PIWIL4) in hepatocellular
carcinoma, and determine its association with clinicopathological features. Methods: Samples from
patients comprising serum and frozen fragments of paired tissue specimens (tumour and adjacent non-
malignant liver tissue) were employed for molecular analyses. Real-time polymerase chain reaction was
performed on 50 tissue and serum samples from HCC patients and 25 serum samples from healthy
controls. Results: The PIWIL1, PIWIL2, PIWIL3, & PIWIL4 levels were significantly (<0.001) higher in both
HCC tissue and serum samples than in the controls. Additionally, the diagnostic performance was
assessed by ROC curves, the PIWIL1-4 levels in serum showed better potential and sensitivity to screen
HCC patients than their levels in tissues. Moreover, some PIWIL elements were found here to be
significantly correlated with the HCC profile. Conclusion: PIWI expression is considered as a powerful non-
invasive diagnostic tool for HCC. Our findings also support the theory that PIWIL expression is critical for
cancer progression.
