Polycyclic aromatic hydrocarbons (PAHs) belong to the group of heat-related contaminants and comprise a large group of organic compounds whose structure consists of at least two fused aromatic rings. PAHs in their original form are lipophilic and low reactive compounds, which are converted to reactive structures only through the process of biotransformation. In non-smokers, the main source of PAH intake is food. The polycyclic compounds found in food result from combustion processes during the processing of, for example, grain products and vegetable oils, and during the smoking of meat products and fish. They are also formed when meat is grilled over open fire. PAHs are always formed in complex mixtures consisting of carcinogenic and non-carcinogenic representatives. However, mixture effects, especially with regard to genotoxic properties of, for example, the already well-studied human carcinogen benzo[a]pyrene (BP), have been little studied so far. To fill these knowledge gaps and to identify combination effects between non-genotoxic and genotoxic PAHs, mixtures of BP with the non-carcinogenic fluoranthene (FA) and pyrene (PYR) in a ratio of 1:2:2.5 were investigated in human HepaRG cells based on the occurrence of PAHs in grilled meat (exposure-based). Analyses included studies of receptor activation of AhR and CAR, gene expression of prominent target genes (CYP1A1 and CYP2B6), and, finally, studies of metabolism of BP and formation of BP-induced DNA damage DNA adducts and DNA double-strand breaks). Our results clearly show that despite significant mixture effects at the molecular level of receptor activation and induction of target gene expression, no substantial mixture effects were observed in the final metabolism and bioactivation of BP. Based on our data, we recommend to investigate and evaluate mixture effects not only by relying on the initiating events but also by examining the biological endpoints such as the influence on metabolism or on the DNA adduct rate.In addition to the exposure-based approach to evaluate the effects of mixtures, effects of 10 structurally-different PAHs (benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[c]phenanthrene, benzo[j]fluoranthene, benzo[k]fluoranthene, dibenzo[a,l]pyrene, fluoranthene, phenanthrene, pyrene) were also investigated first in monoexposure with respect to the interaction with AhR and CAR, the induction of the expression of the target genes CYP1A1/1A2 and CYP2B6, their protein amount and protein activity. Here, small PAHs (up to 4 rings) were found to primarily induce CAR/CYP2B6 and large PAHs (>5 rings) induced AhR/CYP1A1 axis. Following the results, relative potency factors (RPF) for activation of CAR and AhR were calculated for the 10 PAHs based on receptor activation, and then binary mixtures corresponding to BP (RPF=1) were prepared based on the RPFs and receptor activation and target gene expression were reexamined. Finally, the observed effects were compared with the expected effects using three mathematical models. The data from these studies showed that the predictions regarding CAR/CYP2B6 activation were in relatively good agreement, but very little agreement was identified for AhR/CYP1A1 axis activation by the mixtures, which may be associated with the reporter gene assay model or the activation properties of AhR.In summary, the results of our research project show that the analysis of mixture effects is a very complex topic. However, further research in this area is urgently needed, especially research that involves and links multiple endpoints at biological endpoints. Only in this way will it be possible to better evaluate the complex exposure of humans with respect to complex mixtures of xenobiotics.