# Carbazole Derivatives as STAT Inhibitors: An Overview
## 4 Conclusions
\begin{table}
\begin{tabular}{|c|l|c|c|} \hline
**Compound** & **Name Compound** & **Structure Compound** & **References** \\ \hline
**21** & 6-Chloro-1,4-dimethyl-9\(H\)-carbazole & & [PERSON] et al. [115] \\ \hline
**22** & 5,8-Dimethyl-9\(H\)-carbazole-3-sulfonamide & & [PERSON] et al. [115] \\ \hline
**23** & 6-Methoxy-1,4-dimethyl-3-nitro-9\(H\)-carbazole & [PERSON] et al. [115] \\ \hline
**24** & Ethyl-5,8-dimethyl-9\(H\)-carbazole-3-nitro-carb oxalate & [PERSON] et al. [115] \\ \hline
**25** & 6-Methoxy-1,4-dimethyl-9-ethyl-carbazole & [PERSON] et al. [115] \\ \hline
**26** & 6-Methoxy-1,4-dimethyl-9-ethyl-carbazole & [PERSON] et al. [115] \\ \hline
**27** & 3-(3,4-Dicholophenyl)-6-(morpholine-4-carbonyl)-9\(H\)-carbazole-1-carboxylate & & [PERSON] et al. \\ \hline
**28** & (5)-7-(2-(dimethylamino)-pyrrolidine-1-carbonyl)-3-(3-methoxyphenyl)-9\(H\)-carbazole-1-carboxylate & & [PERSON] et al. \\ \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
\begin{table}
\begin{tabular}{|c|l|l|l|} \hline
**Compound** & **Name Compound** & **Structure Compound** & **References** \\ \hline
**29** & 3-(1-Methyl-1\(H\)-indazol-5-yl)-7-(4-methylpiperazin-1-yl)-9\(H\)-carbazole-1-carboxylate & & [116] \\ \hline
**30** & 3′-((3-Acetyl-6-chloro-9\(H\)-carbazol-9-yl)methyl)-[1,1′-biphenyl]-2-carbonitrile & [PERSON] et al. [117] \\ \hline
**31** & 3′-((3-Chlororo-6-ethyl-9\(H\)-carbazol-9-yl)methyl)-[1,1′-biphenyl]-2-carbonitrile & [PERSON] et al. [117] \\ \hline
**32** & 3′-((3-Chlororo-6-(1-hydroxyethyl)-9\(H\)-carbazol-9-yl)methyl)-[1,1′-biphenyl]-2-diphenyl-2-carbonitrile & [PERSON] et al. [117] \\ \hline
**33** & 3′-((3-Chlororo-6-(1-hydroxyethyl)-9\(H\)-carbazol-9-yl)methyl)-[1,1′-biphenyl]-2-carbonitrile & \\ \hline
**34** &  
Figure 16 represents the mechanisms of action of the compounds cited in this review. Some of these studies have also been supported by in silico evaluations. It may be interesting to compare the activity between some successful carbazole and non-carbazole molecules targeting STATs. Indeed, HJC0123, cpd30, cpd188, and carbazole compound 15 demonstrated their ability to target STAT3 and to exert antimuoral effects against breast cancer. Among them, HJC0123 exhibited the lower IC\({}_{50}\) values, amounting to 0.1-1.25 uM. Furthermore, it demonstrated to be orally bioavailable and suppressed tumoral growth in vivo [90]. Concerning compound **15**, its mechanism of action on STAT3 has been deepened, demonstrating its ability to inhibit phospho-STAT3 in the micromolar range. Moreover, other findings also reported interesting activity in an in vivo model of breast cancer in which the tumor suppression occurred after a few days of treatment. All this data, taken together, make compound **15** a promising carbazole lead compound and a potential tool in the fight against cancer. However, further studies able to validate the importance of compound **15** and of other promising carbazoles for clinical use must be carried out. If they succeed, carbazoles could represent a valid alternative to conventional treatments, allowing us to overcome the phenomena of drug resistance, entering, in this way, into the plethora of target therapies. Conceptualization, A.C. ([PERSON]) and C.S. ; methodology, A.B. ; software, G.S. ; resources, A.C. ([PERSON]) and A.B. ; data curation, A.C. ([PERSON]); writing--original draft preparation, A.C. ([PERSON]) and A.B. ; writing--review and editing, A.C. ([PERSON]); supervision, M.S.S. and C.S. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The authors declare no conflict of interest.