Our study aims to investigate the status of some non-traditional metabolic variables in relation to HCC in HCV-induced cirrhotic patients. We estimated the serum levels of vitamin D3, Zinc, parathyroid hormone (PTH), calcium, and phosphate in HCV patients with and without HCC in a trial to study their possible predictive or risk abilities in the development of HCC.
In our study, in the HCC patients, the male distribution is twice more frequent than in females (68% vs 32%); with significantly higher male distribution in the HCC group than in the cirrhotic one (68% vs 45%, p < 0.028). This reflects the male predominance in HCC as has been reported by Hammad et al.17, who stated that HCC was significantly more frequent in males than in females (77.7% and 22.3% respectively). However, in our study, on multiple logistic regression analysis, the sex distribution is not a significant predictor for the occurrence of HCC.
The reasons for this gender disparity could be explained by differences in exposure to risk factors. Furthermore, estrogen is believed to have a protective role against the development of HCC as differences in subtypes of estrogen receptors expressed in males vs. females have been shown to contribute to the progression of HCV related HCC.18
Our data also show that HCC is more common in older age patients; albeit with no significant difference of age between the HCC and non-HCC cirrhotic patients. The age is significantly higher in the HCC and the cirrhotic than in the CHC patients, (p < 0.001). On multiple stepwise logistic regression analysis in relation to chronic liver disease rather than to cirrhosis, older age is found to be significantly associated with HCC (OR: 1.11; 95% CI; 1.02–1.2; P < 0.014). El Zayadi et al.19 have reported that HCC in Egypt is significantly more prevalent among older age groups than younger age groups and they have suggested that HCV infection in old patients induces a rapid progression to HCC independent of HCV genotype. Omata et al.20 have reported that older age is a risk factor for HCC, especially in areas where HCV infection is endemic as in Egypt.
Furthermore, our results show that both the AST and ALT levels are significantly higher in the HCC patients when compared to the non- HCC cirrhotic and CHC patients. The raised AST is significantly associated with HCC (OR: 1.03; 95% CI; 1.01–1.05). At a cut off value of > 50 U/L, AST has sensitivity 76% and specificity 65.71%. This finding is supported by large cohort study that has been done on 1108 patients with HCC by Carr and Guerra21, who have found an association between increasing levels of liver enzymes (AST, ALP and GGT) and HCC aggressiveness.
Our data present significantly lower levels of vitamin D3 in the HCC group compared to the cirrhotic and the CHC groups. Furthermore, vitamin D3 deficiency is significantly more frequent in patients with HCC (96%) compared to the cirrhotic and chronic hepatitis patients, (p < 0.001). These results are similar to those of a study done by Finkelmeier et al.22, who have measured vitamin D3 in 200 patients with HCC and cirrhosis and have compared its level to the stages of both HCC and stages of cirrhosis based on MELD, CTP, BCLC, and The Cancer of the Liver Italian Program (CLIP) scores. In their study, vitamin D3 levels are negatively correlated with the stages of cirrhosis as well as stages of HCC. Furthermore, their patients with severe vitamin D3 deficiency had the highest mortality risk. Our study indicates that the mean vitamin D3 levels are not significantly different between the cirrhotic and the CHC patients. However, vitamin D deficiency is more frequent in the cirrhotic than in the CHC groups (22.5% vs zero%, respectively; p = 0.004). This later finding is in agreement with Duarte et al.23, who have studied vitamin D3 level in 100 patients with chronic viral hepatitis, (49 noncirrhotic and 51 with cirrhosis), where they have found that vitamin D3 was low in only 3 cirrhotic patients without significant difference between the cirrhotic and the non-cirrhotic groups. However, Miroliaee et al.24 have reported that vitamin D deficiency is significantly more frequent in cirrhotic patients compared to non-cirrhotic patients (76.5 vs.17.9%; p = 0.001).
Vitamin D3 and its derivatives have immune, neuroendocrine activities, anti-carcinogenic properties.25,26 Recently, Diaz et al.27 have reported the ability of vitamin D3 to enhance the anti-tumor activity of chemotherapeutic drugs by activating apoptosis. However, a causal relationship has remained mostly unclear because most of the studies were small or concentrated on the assessment of vitamin D3 serum levels at the date of HCC occurrence which may result in false statistical associations due to the influence of impaired liver function on circulating vitamin D3. Another study done by Caputo et al.28 has reported an inhibitory effect of vitamin D3 on the growth of the human liver cancer cell lines which express functional receptors able to specifically bind vitamin D3.
Although our results indicate significant very low levels of vitamin D3 in HCC patients with more significant frequency of its deficiency, yet on multiple stepwise logistic regression analysis, vitamin D3 is not a significant independent predictor for HCC. It is not clear whether this reflects a type two statistical error due to the small sample size or this deficiency may reflect a functional synthetic error for vitamin D3 by the HCC diseased liver rather than a risk factor for HCC development.
We also investigated serum Zinc levels in our study groups. Our results show that Zinc level is significantly lower in patients with hepatocellular carcinoma compared to levels in liver cirrhosis and CHC patients This finding is in agreement with results reported by other studies.29,30 HCC malignancy is ZIP14-deficient tumor, so with Zinc deficiency, the abolished cytotoxic effects of Zinc on malignant cells cannot be ruled out and low Zinc levels may predispose patients to HCC development. At the same time, the malignant cells derive adaptation mechanisms through which they lower down the concentration of zinc to avoid its cytotoxic effects on them at normal zinc levels30. A recent study has reported data about the protective role of long-term Zinc supplementation against development of HCC.31 However, again, in spite of the significant low levels of zinc in our HCC patients, yet on multiple stepwise regression analysis, zinc is not a significant predictor for HCC.
Our results indicate a significant higher level of serum PTH in patients with HCC compared to its levels in the cirrhotic and the CHC patients. In addition, the serum PTH significantly increases in patients with liver cirrhosis in comparison to CHC patients. When multiple stepwise logistic regression analysis was done in relation to CLD rather than cirrhosis, PTH, age, AST and corrected calcium levels were significantly associated with HCC, Table (6). PTH is considered a predictor for HCC (OR: 1.11; 95% CI; 1.004–1.02; P < 0.014) at cut off value of > 100 ng/l with sensitivity 84% and specificity 74.29%.
On the other hand, our study shows statistically significant higher level of corrected calcium in patients with hepatocellular carcinoma compared to levels in liver cirrhosis and CHC patients. Our data show also that the corrected calcium is one of HCC independent predictive factors (OR: 4.0; 95%CI: 2.3–6.9; p < 0.001). Corrected calcium at a cut-off value of (> 9.63) had sensitivity 82% and specificity 75.71% in the prediction of HCC in relation to chronic liver disease. Hypercalcemia associated with malignant disease is not uncommon. This is ascribed to both bony metastatic lesions and the production of parathyroid hormone-related protein (PTHrP) from the malignant cells.32 Two case reports have described cases with hypercalcemia that is caused by HCC secreting intact parathyroid hormone (iPTH).33,34 When effective, Trans Arterial Chemoembolization (TACE) against the HCC results in stepping down the serum iPTH level and calcium to within the normal range, suggesting a correlation between the carcinoma and the iPTH.35