The Threat of Multiple Liver Carcinogens in the Population of Laos: A Review
Round 1
Reviewer 1 Report
nice piece of work summing up the state of knowledge on HCC in Laos.
Is there any element of alcoholic and non-alcoholic liver disease contributing to HCC in this country? In both positive and negative cases, it might be worth mentioning as a separate paragraph
Author Response
Nice piece of work summing up the state of knowledge on HCC in Laos.
Is there any element of alcoholic and non-alcoholic liver disease contributing to HCC in this country? In both positive and negative cases, it might be worth mentioning as a separate paragraph.
We thank the reviewer for these suggestions and of course agree with her/him all the more easily that another reviewer asked for the very same improvement. A new part dealing with fatty liver diseases (alcoholic liver disease and non-alcoholic fatty liver disease) has been added pages 5 and 6.
Reviewer 2 Report
Comments and Suggestions for Authors
The manuscript entitled “The threat of multiple carcinogens in the population of Laos: a Review” by Philavanh Sitbounlang et al. carry out an exhaustive review of liver diseases that affect the Laotian population, suggesting that the main cause of this disease could be a double infectious burden of HVB and HCV and O. viverrine, in addition, they do not rule out mutagenic substances found in the tobacco, alcohol and some foods consumed by this population.
The manuscript has interesting information on the risk factors of high prevalence in the Lao population of presenting primary liver cancer. However, I suggest important and weighty observations to improve this scientific review.
Line 38: please change “35%” into (> 35%).
Line 39, 64, 66, 79, 85, 158, 168: the abbreviations should be defined in parentheses the first time they appear in the text. Change “PLC” into (PLC).
Line 40-41: I think what you mention is not correct, since these countries are not in the figure as you point out. Please change “fifth highest rate worldwide behind Mongolia, Egypt, Gambia, and Viet Nam” into second highest rate in Southeast Asia, behind Vietnam.
Line 41 and Figure 1: please change “Viet Nam” into Vietnam
Line 58: remove italics in “by”
Line 63: place the comma between the two hepatitis words.
Line 70: change “in medical literature” into in the medical literature.
Line 85: change “occult B infection” into occult hepatitis B infection.
Line 92: place the reference at the end of the paragraph.
Line 111: what does the abbreviation VL mean?
Line 171: place the reference at the end of the paragraph.
Line 191-192: change the next sentence “as it was shown to generate g-to-t 191 mutations at codon 249 of TP53 gene leading to the replacement of an ARG by a SER” into as it was shown to generate mutations due transversion of G to T at codon of TP53 gene leading to the replacement of an ARG by a SER.
Line 197: remove the abbreviation PLC.
Figure 3: Improve the scheme, since the liver, gallbladder, OV, and arrows do not have good quality. Also, place the meaning of the abbreviations in the legend of the figure.
For completeness of your review, I suggest adding information on primary liver cancer and its relationship with obesity. This is because the authors mention the incidence of overweight people in Southeast Asia, which could also be a risk factor for the population of Laos, contributing to the incidence of liver cancer. This encourages further research to correlate overweight with the risk factors mentioned in this scientific review.
With respect to the above-mentioned, in Figure 3: Is it possible to include schematically obesity (lipid accumulation, insulin resistance, oxidative stress, among others.)? This is a possible carcinogenic risk factor.
Comments for author File: 
Comments.pdf
Author Response
The manuscript entitled “The threat of multiple carcinogens in the population of Laos: a Review” by Philavanh Sitbounlang et al. carry out an exhaustive review of liver diseases that affect the Laotian population, suggesting that the main cause of this disease could be a double infectious burden of HBV and HCV and O. viverrine, in addition, they do not rule out mutagenic substances found in the tobacco, alcohol and some foods consumed by this population.
The manuscript has interesting information on the risk factors of high prevalence in the Lao population of presenting primary liver cancer. However, I suggest important and weighty observations to improve this scientific review.
Line 38: please change “35%” into (> 35%).
We changed this notation for that asked by the reviewer.
Line 39, 64, 66, 79, 85, 158, 168: the abbreviations should be defined in parentheses the first time they appear in the text. Change “PLC” into (PLC).
All abbreviations were included in parentheses at their first appearance in the text (eg PLC, HCC, CCA, HBV, HCV, OBI, OV, Sm, PAH, AFB1, ALD, NAFLD, BMI, NCD, etc…).
Line 40-41: I think what you mention is not correct, since these countries are not in the figure as you point out. Please change “fifth highest rate worldwide behind Mongolia, Egypt, Gambia, and Viet Nam” into second highest rate in Southeast Asia, behind Vietnam.
We brought the change rightfully requested by the reviewer.
Line 41 and Figure 1: please change “Viet Nam” into Vietnam
We changed for Vietnam.
Line 58: remove italics in “by”
We changed in “by”.
Line 63: place the comma between the two hepatitis words
We placed the comma as requested.
Line 70: change “in medical literature” into in the medical literature.
We changed for “into the medical literature”.
Line 85: change “occult B infection” into occult hepatitis B infection.
We brought the change as asked.
Line 92 and 171: place the reference at the end of the paragraph.
We placed the reference at the end of the paragraph.
Line 111: what does the abbreviation VL mean?
We replaced “VL” with “viral load”.
Line 191-192: change the next sentence “as it was shown to generate g-to-t 191 mutations at codon 249 of TP53 gene leading to the replacement of an ARG by a SER” into as it was shown to generate mutations due transversion of G to T at codon of TP53 gene leading to the replacement of an ARG by a SER.
We changed our sentence for that suggested by the reviewer.
Line 197: remove the abbreviation PLC.
We removed the abbreviation.
Figure 3: Improve the scheme, since the liver, gallbladder, OV, and arrows do not have good quality. Also, place the meaning of the abbreviations in the legend of the figure. Is it possible to include schematically obesity (lipid accumulation, insulin resistance, oxidative stress, among others)? This is a possible carcinogenic risk factor.
We added the meaning of each abbreviation in the legend and modify the figure by adding a steatosic area in the liver together with its associated risk factors (ethanol intake, overnutrition).
For completeness of your review, I suggest adding information on primary liver cancer and its relationship with obesity. This is because the authors mention the incidence of overweight people in Southeast Asia, which could also be a risk factor for the population of Laos, contributing to the incidence of liver cancer. This encourages further research to correlate overweight with the risk factors mentioned in this scientific review.
We thank the reviewer for these suggestions and of course agree with her/him all the more easily that another reviewer asked for the very same improvement. A new part dealing with fatty liver diseases (alcoholic liver disease and non-alcoholic fatty liver disease) has been added on pages 5 and 6.
Reviewer 3 Report
All in all this was a very informative read, and interesting paper. Just a few minor points.
Line 38: …a high proportion of the ?? is overweight. Population?
Methods: What was your inclusion criteria? Can you be specific about how you decided which papers to include/exclude?
Line 82: …and this rate remained stable 9.6% in a more recent study. Maybe ‘…and this rate remained stable at 9.6%...’ or you could state that it remained stable, but steadily increasing.
Line 167: Sentence starting ‘During this accelerated tissue repair process….’ There are many claims in this sentence, but no references. It would be good to add a few references supporting how these substances contribute to mutations that promote tumor processes.
General: PLC is stated as the acronym for primary liver cancer at the start of this paper. There is no need to repeat it, for instance in the conclusion. Just use PLC throughout.
What are the reasons that people in Laos are not being vaccinated for Hepatitis?
Author Response
Comments and Suggestions for Authors _Reviewer#3
All in all this was a very informative read, and interesting paper. Just a few minor points.
Line 38: …a high proportion of the ?? is overweight. Population?
We added the forgotten word
Methods: What was your inclusion criteria? Can you be specific about how you decided which papers to include/exclude?
We provide now details about the way we handled the current literature:
“Our search was targeted on terms corresponding to liver diseases and carcinogenic factors in the region (hepatitis viruses B and C, O. viverrini, aflatoxin B1, nitrosamines, alcoholic beverage, fatty liver, liver cirrhosis, liver cancer, cholangiocarcinoma, hepatocellular carcinoma) AND country names. We primarily focused our search on the literature treating from Laos (or Lao People’s Democratic Republic, Lao PDR also frequently used in the medical literature) but when no record was available we explored publications from immediately neighboring countries (Cambodia, Myanmar, Thailand, Vietnam). Relevant medical literature from China was only marginally approached and mostly focused on the Yunnan province, the only Chinese province to share a border with Laos. Articles were first selected after reviewing the title and abstract and subsequently by reading the full text of papers retained”
Line 82: …and this rate remained stable 9.6% in a more recent study. Maybe ‘…and this rate remained stable at 9.6%...’ or you could state that it remained stable, but steadily increasing.
We followed the suggestion of the reviewer and change the sentence for:
“…this rate remained stable but steadily increasing (at 9.6%) in…”
Line 167: Sentence starting ‘During this accelerated tissue repair process….’ There are many claims in this sentence, but no references. It would be good to add a few references supporting how these substances contribute to mutations that promote tumor processes.
We added four references describing the main mutagenic processes:
- Hussain, S.; Schwank, J.; Staib, F.; Wang, X.; Harris, C. TP53 mutations and hepatocellular carcinoma: insights into the etiology and pathogenesis of liver cancer. Oncogene 2007, 26, 2166-2176.
- Nedelko, T.; Arit, V.; Phillips, D.; Hollstein, M. TP53 mutation signature supports involvement of aristolochic acid in the aetiology of endemic nephropathy-associated tumours. Int J Cancer 2009, 124, 987-990.
- Tanase, A.; Marchio, A.; Dumitrascu, T.; Dima, S.; Herlea, V.; Oprisan, G.; Dejean, A.; Popescu, I.; Pineau, P. Mutation Spectrum of Hepatocellular Carcinoma from Eastern-European Patients betrays the Impact of a complex Exposome. J Exp Sci Env Epidemiol 2014, 25, 256-263.
- Zhang, W.; He, H.; Zang, M.; Wu, Q.; Zhao, H.; Lu, L.; Jiao, Y. Genetic features of aflatoxin-associated hepatocellular carcinoma. Gastroenterology 2017, 153, 249-262.
General: PLC is stated as the acronym for primary liver cancer at the start of this paper. There is no need to repeat it, for instance in the conclusion. Just use PLC throughout.
We changed for PLC throughout. However, we let it in the abstract and when it appears for the first time in the legend to the figure 1.
What are the reasons that people in Laos are not being vaccinated for Hepatitis?
This is a difficult question asking for a complex answer. Although several mass vaccination campaigns have been organized in Laos since 2001, HBV prevalence remains a challenging health problem in the country. Less than 30% of newborns receive HBV birth dose coverage. Populations generally accept vaccination and are aware of its benefits. However, in some mountain areas, access to medicine is relatively recent; people remember buying medication only in the last 20 years. In some remote regions, previously mentioned vaccination programs began only in 2006. Villagers explained that they were at first reluctant towards vaccination but now accept it due to tangible health benefits. All these changes were, thus, brought recently in the history of Laos and it explains why HB-associated liver cancer incidence is still high and will probably continue to be so in the next decades.
This information has been found in a report to the Ministry of Health, “Issues, barriers, and facilitators that influence access to immunization programs for people living in the Mekong border regions of Lao PDR” written among others by to authors of the current revised paper (E. Deharo and P. Paboriboune, 2018). This report is now referenced in the paper (ref#15).
Round 2
Reviewer 2 Report
The manuscript has improved considerably. Just make a correction on the line 232. The correct term for NAFLD is non-alcoholic fatty liver disease.
