The Expression And Clinical Significance Of Progesterone-induced Blocking Factor Splice Variant In Hepatocellular Carcinoma

Background and ObjectiveProgesterone-induced blocking factor (PIBF) is found initially as animmunomodulatory molecule secretion of γ/δ TCR-positive pregnant lymphocyte, whichmay help the immune escape of the embryo, from the parent monitor. PIBF in the body is intwo forms: one for full-length PIBF, approximately90-kDa, is located in the nucleus, nosecretion function; another way is PIBF splice variants, in different sizes, mostly are34-kDa, diffuse distribution in cytoplasm, with secretion function. Many researches has beenshown the over expression of full length PIBF in multiple tumor cell lines, but the results inthe human body tissues and fluids and on the relationship between splice variants secretedPIBF and tumor are rarely reported. In recent years, primary liver cancer incidence andmortality in most countries of the world showed an upward trend. Our country is a highincidence of liver cancer, which hepatocellular carcinoma (HCC) accounted for more than90%of primary liver cancer. AFP，the tumor marker of HCC，is a common embryonicsecreted protein. The study try to detect the expression of PIBF splice variant in the serumand tissue of patients with HCC and seek the relationship between the expression of PIBFand the amount of Ki67-positive cells and the degree of tumor differentiation, explore itsexpression in hepatocellular carcinoma and possible clinical significance.MethodsUse ELISA to detect the serum concentration of PIBF splice variant in healthy personsand patients with HCC. Western blot detect the expression of PIBF splice variant of normalliver tissues, HCC tissues and its corresponding paraneoplastic tissues. Useimmunohistochemistry to detect the expression of PIBF splice variant of HCC tissues andtheir corresponding paraneoplastic tissues. Use x±s to express the normally distributed measurement data and use line independent sample t test, paired t test, ANOVA, LSD test,Chi-square test or Spearman rank correlation test.Results1. The PIBF splice variant serum expression level in patients with overall HCC is49.10±4.07ng/ml, and in healthy people is73.04±6.29ng/ml (t=3.23, P=0.010). Theserum PIBF splice variant concentrations in HCC patients with first onset, HCCrecurrence patients and healthy people are52.06±5.05ng/ml,41.98±6.62ng/ml and73.04±6.29ng/ml (F=5.606, P=0.004). The P value between HCC patients with firstonset and HCC recurrence patients is0.375. The P value between HCC patients with firstonset and healthy people is0.011. The P value between HCC recurrence patients andhealthy people is0.005. Postoperative day1，all of postoperative serum PIBF splicevariant reduced（t=4.267，P=0.001）. Postoperative day5，most of postoperative serum PIBFsplice variant have different degrees compared with preoperative increased (t=3.108, P=0.008). The serum expressions of PIBF splice variant of recurrence HCC patients is22.06±2.60ng/ml, lower than normal (t=2.972, P=0.004). The serum PIBF splice variantexpressions of healthy male and female are80.14±1.23ng/ml and65.79±8.51ng/ml (t=1.142, P=0.256).The serum expressions of PIBF splice variant in male and female HCCpatients are49.28±4.85ng/ml and48.79±7.40ng/ml (t=0.057, P=0.955).2. Take β-actin as an internal reference, the average relative PIBF splice variantexpression in HCC tissue is0.12±0.04, normal liver tissue is0.63±0.20(t=2.479, P=0.039). With GAPDH as an internal reference, most of the paraneoplastic tissues PIBFsplice variant express higher than the cancer tissue (t=2.385, P=0.049).3. The high expression rate of PIBF splice variant in HCC tissues is6.25%. The highexpression rate in paraneoplastic tissues is97.92%. To compare two group, t=20.076，P=0.000.4. The PIBF splice variant and percentage of Ki67-positive cells in HCC tissue isnegatively correlated （r=-0.714， P=0.000）. The positive expression rate of lowdifferentiation HCC was81.8%, and The positive expression rate of high differentiationHCC was37.1%（χ2=6.695，P=0.010）.5. The PIBF splice variant concentration in serum and percentage of Ki67-positivecells in HCC tissue is negatively correlated.（r=-0.617，P=0.000）. The serum PIBF splice variant concentrations in poorly differentiated, moderately differentiated, well-differentiatedHCC patients is21.16±3.53ng/ml,42.83±5.52ng/ml,72.76±7.52ng/ml (F=9.176,P=0.000). I-J and P value between poorly differentiated and moderately differentiatedtissue are21.67and0.019. I-J and P value between poorly differentiated andwell-differentiated tissue are51.60and0.000. I-J and P value between moderatelydifferentiated and well-differentiated tissue are29.93and0.007.Conclusion1. The serum concentrations of PIBF splice variant in HCC is lower than normalpeople. It turns to nomal level after opereation and reduced in recurence patient.The PIBFserum concentrations is no significant gender differences in HCC patients with first onsetand HCC recurrence patients, and lower than healthy people. The PIBF serumconcentrations is lower post operation.2. HCC tissue PIBF splice variant content is lower than normal liver tissue. the splicevariant PIBF levels in HCC tissues is lower than their corresponding peritumoral tissues andparaneoplastic tissues.3. The PIBF splice variant concentration in serum and percentage of Ki67-positivecells in HCC tissue is negatively correlated. The lower the PIBF splice variant expression,the cell proliferation is stronger.4. The PIBF splice variant is related to the degree of differentiation. The lowerexpression of PIBF splice variant, tumor differentiation worse.