However, HCV infection is associated with early onset BC [17] or not [6], and other important studies found an association between chronic HCV infection and BC severity [9]. In a previous study, although there was no association between HCV positivity in BC patients compared to patients with benign diseases (27.5 vs. 23.7%), our team found that HCV-NS4 was increased in BC HCV-infected patients compared to HCV-infected patients with benign diseases [9]. Elevated viral protein levels were related to tumor severity including infiltrated lymph-node high grades, late stages, and large size [9]. Here, we investigated the association between the impact of HCV infection on BC progression and mutant p53 and c-Myc oncoproteins’ expression.

First of all, HCV infection was more frequent in patients with tumor aggressiveness features including late stages (70.8 vs. 29.2%), lymph-node invasion (59 vs. 41%), distant metastasis (68.5 vs. 31.5%), high grades (65.8 vs. 34.2%), and large size (62.3 vs. 37.7%). Regarding clinical data, and compared to HCV non-infected patients, HCV-infected patients had significantly higher WBCs, ALT and AST activity and bilirubin levels, and reduced hemoglobin, albumin, and RBCs’ count. Moreover, HCV infection was associated with elevated CEA, CA125, and CA15.3 levels.

These results are in consistent with other limited reports that deal with the impact of HCV viral infection on BC severity. Some HCV-related viral proteins may promote the regulation of some gene expression that may be accompanied with transformation, apoptosis inhibition, and tumorigenesis [9, 18]. Elevated HCV-NS4 protein levels were significantly related to BC severity including advanced stages, high histological grades, large tumor size, and lymph-node invasion [9]. Regarding other BC clinically relevant aspects, other studies also may be in the same line with our findings were concerning with the impact of HCV infection on BC patients receiving chemotherapy. They found that HCV‐positive patients were associated with significantly high risk of longer time to complete treatment, dose delays, dose modifications, hematotoxicity-related dose delays, and hospitalization during chemotherapy [19].

Interestingly, compared to non-infected BC patients, we found that HCV-infected patients were associated with significant high levels of mutant p53 (1.9-fold increase) and c-Myc (1.5-fold increase) proteins. Regardless of tumor severity, these elevated levels of the two oncoproteins were associated with HCV infection. As, at the same tumor stage, BC women who infected with HCV had 1.4- and 1.7-fold increase in p53 and c-Myc levels, respectively, compared to patients without infection. The same was obtained regarding lymph-node invasion, distant metastasis, tumor grade, and tumor size. Moreover, the elevated levels of mutant p53 and c-Myc were positively correlated with elevated CEA, CA 125, and CA15.3 and also with HCV-NS4 [r = 0.405, P < 0.0001 for p53; r = 0.349, P < 0.0001 for c-Myc].

In HCV-related HCC, mutations of P53 were common particularly in Africa [20, 21]. Moreover, P53 nucleotide change were more frequent in HCV-related than in HBV-related HCC [21]. In BC, P53 is the most commonly mutated gene. Its mutations inhibit its transcriptional activity and are greatly related to progression and poor survival in BC patients [22]. P53 mutations was reported to be higher in high-grade and advanced-stage BC and these mutations have been related to BC with aggressive behavior like TNBC [23]. Besides inhibition of p53 functions, mutations in p53 can acquire oncogenic activity by gain-of-function (GOF) mechanisms that has been reported to promote genome instability [24]. Mutant p53 also can increase expression of chromatin-regulated genes which related to enhanced histone acetylation and methylation and contributes to BC progression [25]. Also, elevated mutant p53 levels are associated with many events that related to poor clinical outcomes and increased BC metastasis and invasion [22], including evading apoptosis [26] and activation of the transcription of many genes related to cell proliferation [27].

There was a mechanistic link between enhanced c-Myc expression and HCV infection [28]. In transgenic murine model expressing the entire HCV open-reading frame, elevated c-Myc expression was reported in vivo, suggesting a direct role of HCV protein expression in c-Myc induction. Through Akt activation and subsequent β-catenin stabilization, HCV non-structural proteins were reported to be responsible for c-Myc promoter activation [28]. In the majority of human tumors, c-myc oncogene is deregulated or amplified [29]. c-Myc drives several aspects of cancer metastasis and progression by promoting cell proliferation and survival, differentiation block, genetic instability, cell invasion, and migration [30]. In BC, c-Myc overexpression is frequent in invasive and high-grade tumors and is consistently related to early recurrence and poor outcome [31, 32]. In this context, c-Myc also promotes tumor-associated macrophages’ activation, which increase tumor’s aggressiveness [33]. Compared to HER2 and ER/PR + amplified BCs, c-Myc is disproportionately elevated in triple-negative BC (TNBC) [34]. Distant lethal BC metastases from c-Myc-unamplified primary cancers often gain c-Myc amplification [35]. Even when it is not overexpressed, the cancer microenvironment is maintained by c-Myc through inflammation, angiogenesis, and instructing tissue remodeling [36]. Inhibition of c-Myc was recently reported to stop progression of metastatic BC by blocking seeding, invasion, and growth [30].

In conclusion, this study findings concluded that HCV infection in BC patients may be accompanied with severity behavior of the tumor. These effects may be owing to the elevated expression of mutant p53 and c-Myc oncoproteins as HCV-infected BC patients were associated with elevated levels of these oncoproteins and subsequent severity features, including late stages, high histological grades, lymph-node invasion, and distant organ metastasis. Future large multicentre studies to confirm these results and investigate other mechanistic links between the concurrent HCV and BC are warranted. Also, other in vitro and in vivo studies are needed to perform experiment to clarify whether HCV infection causes increasing p53 and c-Myc proteins.