HCC is commonly a disease of infectious origin; consequently, it could be preventable (El-Tonsy et al. 2013). In the present study, the association of S. mansoni with HBV and/or HCV was investigated as a risk factor for the development of HCC. A total of 90 HCC cases were eligible for this study; they were categorized into HCC patients negative for schistosomiasis (62 patients) and HCC patients positive for schistosomiasis (28 patients).
In this study, the larger proportion of HCC positive for S. mansoni was in the age group 50–60 years with no statistical significance. Abdel-Wahab et al. (2007) and El-Zayadi et al. (2005) revealed different findings and the predominant age was 40–59 years, this was explained by the different localities, the risk of exposure and the study periods. As for gender, HCC was more prevalent in males than females (3:1) in the two groups with no significant difference. Concordant results were obtained by El-Zayadi et al. (2005) and El-Tonsy et al. (2016) concerning gender.
Considering residence, the rural areas dwelled patients showed that HCC was 1.5 times higher than those living in urban areas (63% vs 36% respectively) with no statistically significant difference. These findings agreed with those of Abdel-Wahab et al. (2007) and El-Tonsy et al. (2016), which attributed the high prevalence in rural areas to the use of insecticides, pollution, and aflatoxins.
Regarding the clinical data, gastrointestinal hemorrhage in patients with HCC is common and is a major contributor to mortality (Srivastava et al. 2000). The present results revealed that upper GIB was highly significant among positive S. mansoni group compared to the negative one. Consistently, it was reported that schistosomiasis fibrosis is associated with several vascular changes within the host. The peripheral destruction of the portal vein system with the obstruction of some medium-sized branches explains the presence of portal hypertension (one of the S. mansoni infection complications) which leads to upper GIB (Johnson, 2006; Kumar et al. 2008; Andrade, 2009).
During the present study period, 88.9% and 7.8% of HCC patients had HCV and HBV correspondingly without statistically significant difference among the two groups, despite the higher proportion of HCC patients showing concomitant HCV and S. mansoni. The development of a vaccine against HBV explains its lower prevalence. Similar results were reported by Abdel-Wahab et al. (2007), Shaker et al. (2013) and Zampino et. al. (2015). Regarding, S. mansoni and HCV co-infection, El-Zayadi et al. (2005) and Toda et al. (2015) described that Schistosoma infection may modify the sequence of hepatitis C and lead to more significant complications and faster progression to HCC than patients with no schistosomiasis parasite burden. Instead, Hassan et al. (2001) concluded that HCV infection increases the risk of HCC whereas S. mansoni infection does not. Currently, Egypt succeeded to transform HCV from a health system stigma to a global success story through the 100 million healthy lives initiative launched in October 2018. Hopefully this may lead to lowering the prevalence of HCC.
Regarding the liver enzyme levels (SGPT, SGOT), total bilirubin, direct bilirubin and albumin, they were higher in HCC S. mansoni positives compared to S. mansoni negatives yet not statistically significant. Regarding the INR, there was a statistically significant difference between both groups. The concomitant infection or over infection with HCV in patients with schistosomiasis could be the cause of provocation of liver damage and subsequently reduction in coagulation factors production leading to prolonged prothrombin time. Similarly, Kamal et al., 2000a reported more fibrosis in liver biopsies in S. mansoni and HCV concomitant infections compared to HCV mono- infection.
The present results showed that AFP values ranged between 1.5 and 16800 IU/ml in all cases. Although the AFP level in the two studied groups showed no statistical difference, its mean value in the S. mansoni positive group was higher than that in the negative one (1830.5 and 973.0 IU/ml respectively). It was reported that the increased levels in high risk patients provide HCC diagnostic clues. Yet, normal level does not exclude its presence. It was reported that 10–30% of HCC patients have negative AFP expression. On the contrary, many investigators believe that AFP is significant in predicting HCC recurrence and evaluating the biologic features of tumors and treatment regimens (Kamal et al. 2000a; Hu et al. 2022). It was pointed out that AFP prevalence among HCC is accompanied by certain controversies and needs novel directions for prospective studies (Lee et al. 2019; Hu et al. 2022).
In the current study, the Child-Pugh classification revealed no significant difference between the two studied groups. However, BCLC classification showed significant statistical difference between the two groups regarding class (D). Therefore, the concomitant association of HCV and schistosomiasis may have increased the severity of liver pathology and progress of HCC.
As for the role of S. mansoni in inducing HCC, cumulating findings of human clinical investigations and experimental research in animal models on a molecular level suggest S. mansoni is potentially associated with HCC. This association was explained by its activation of the proto-oncogenes; c-Jun signal transducer and transcription 3, whose role in liver inflammation and carcinogenesis is well established (Calvisi, 2020, Shousha et al, 2021). This study together with others suggest thatchronic inflammation resulting from prolonged parasitic infections may encourage carcinogenesis by three mechanisms; first, chronic inflammation that damages host cell and gene expression by supporting the release of reactive oxygen and nitrogen species; second, insertion of oncogenes into the host genome particularly in the presence of hepatitis B and hepatitis C, stimulation of mitosis and inhibition of tumor suppressors; third, reduction of immune response and induction of immune suppression (el-Zayadi et al. 2005; El-Tonsy et al. 2013; Toda et al. 2015; Abdelghani et al. 2020).
In conclusion, although in the current study, the co-occurrence of S. mansoni with HCV and HBV quickens hepatic dysplastic changes and accelerates cancer progression yet; these associations are still being sorted out. So, further studies on large cohorts of HCC patients are essential.