Keywords
Cancer - clonorchiasis - opisthorchiasis - parasite - schistosomiasis - vaccine
Introduction
Cancer is an important problem at present. Of several causes of cancer, infection
is the important underlying factor. The well-known situation is the papillomavirus
infection that can result in carcinogenesis.[1] At present, the cancer vaccine against papillomavirus infection-related cancer,
cervix cancer, is available and used worldwide.[2] Nevertheless, there are also other infections that can induce the cancers. The forgotten
group of problematic infections is the parasitic infections. In fact, there are many
tropical parasitic infections that are still present public health problem in tropical
medicine.[3] Of interest, some diseases are proved for the relationship with carcinogenesis.
Many cancers are proved for the etiopathogenesis due to parasitic infections. The
well-known tropical parasitic infections that can induce carcinogenesis are opisthorchiasis,
clonorchiasis, and schistosomiasis. Opisthorchiasis and clonorchiasis are proved as
the causes of hepatobiliary cancer.[4]
[5] Schistosomiasis is proved as the cause of urinary tract cancer, especially for urinary
bladder cancer.[6] To prevent cancer due to the parasitic infection is the important consideration
in oncology. The standard practice is the prevention of the infection, but the hope
is the development of the new vaccines for cancer prevention. Here, the authors briefly
review on the current status on the cancer vaccines against the three important tropical
diseases that can result in cancers, opisthorchiasis, clonorchiasis, and schistosomiasis.
Vaccine for Opisthorchiasis and Opisthorchiasis-Related Cholangiocarcinoma
Vaccine for Opisthorchiasis and Opisthorchiasis-Related Cholangiocarcinoma
Opisthorchiasis is the liver fluke infection. The main pathogenic species is the Opisthorchis viverrini. This infection is very common in tropical Indochina in Southeast Asia. The chronic
opisthorchiasis is proved for a relationship with cholangiocarcinoma carcinogenesis.[5] Of interest, the extremely high incidence of cholangiocarcinoma can be seen in Indochina.[7] The patients usually present with severe hyperbilirubinemia, and the disease is
usually advanced.[8] High fatality can be seen. The infection usually starts with consumption of raw
fish dishes contaminated with parasitic metacercaria and the food sanitation is widely
promoted in the endemic area.[9] Nevertheless, it is still not successful for disease control.[7]
The new cancer vaccine is the hope for the management of opisthorchiasis-related cholangiocarcinoma.[10] There are some reports on vaccine development from research centers in the tropical
areas. Most reports are on the finding of the epitopes based on the parasitic composition
that can be further used for vaccine development.[11] Nevertheless, there are already reports on the trial of newly developed vaccine
as a therapeutic vaccine against cholangiocarcinoma. The interesting report is on
the development of personalized peptide vaccine against cholangiocarcinoma.[12] Löffler et al. reported the success in the development of personalized peptide vaccine for the
treatment of a patient with cholangiocarcinoma.[12]
Vaccine for Clonorchiasis and Clonorchiasis-Related Cholangiocarcinoma
Vaccine for Clonorchiasis and Clonorchiasis-Related Cholangiocarcinoma
Clonorchiasis is also a liver fluke infection, but the pathogen is the Clornorchis spp. This infection can be chronic and can also result in cholangiocarcinoma carcinogenesis.[13] The same mode of infection acquiring is by intake of poorly cooked contaminated
fish dishes, same as the case of opisthorchiasis. Similar to opisthorchiasis, there
are some ongoing researches on vaccine finding against clonorchiasis-related cholangiocarcinoma.[14] The finding and approval of immunogenicity property of the heat shock proteins 70
and 90 from the parasite is the hope for further vaccine development.[15] In addition, some ongoing researches are also performed regarding cysteine protease
of Clonorchis spp., which is proposed as another important target for vaccine development.[16]
Vaccine for Schistosomiasis and Schistosomiasis-Related Urinary Bladder Cancer
Vaccine for Schistosomiasis and Schistosomiasis-Related Urinary Bladder Cancer
Schistosomiasis is blood fluke infection caused by pathogenic Schistosoma spp. The urinary schistosomiasis, by Schistosoma haematobium infection, is proved for the urinary tract carcinogenesis induction.[6] This disease is highly endemic in tropical Africa and becomes the big public health
problem. In tropical Asia, this infection is sporadically seen.[17] For disease prevention, finding for new vaccine is the present hope. There are some
ongoing researches on vaccine finding against schistosomiasis-related cancer.[18]
[19] Hsieh et al. noted that the vaccine against schistosomiasis would be available within a few years
and would be the third vaccines against the infections that could result in carcinogenesis,
following hepatitis B vaccine and human papillomavirus vaccine.[19] The interesting focus for vaccine development is protein of the mansoni parasite
that is approved for immunogenicity property against Schistostoma spp.[20]
[21] For human vaccine, a recent publication in 2017 mentioned that there will be a human
trial on new vaccine candidate, “Sm-p80-Based Schistosomiasis vaccine” which will
be an important step in the development of vaccine against schistosomiasis and schistosomiasis
cancer.[22]
Conclusion
Although it has been known for many years that some parasitic infections can induce
carcinogenesis, there are few researches for the development of new cancer vaccines
against those parasitic infections. Since those parasitic infections are usually endemic
in poor tropical endemic countries and there are usually limited budget and grant
for research on the cancer vaccines regarding those neglected tropical diseases, the
success in vaccine development might not be available soon. It is necessary to call
for research and development on the vaccine for parasitic diseases with carcinogenesis
property.
