Targeted Sequencing in Gastric Cancer: Association with Tumor Molecular Characteristics and FLOT Therapy Effectiveness

Round 1

Reviewer 1 Report

This study was to investigate the relationship of targeted genetic markers in GC patients with clinical and morphological features of the tumor, as well as the FLOT chemotherapy effectiveness. Liudmila V. Spirina et.al used the the method of amplification of genomic DNA regions to detected the samples of tumor and unchanged tissue. The results find that molecular features of tumors determined by significant genetic markers can modify the biological properties of tumors and influence the efficacy of antitumor treatment.

There are some limits in this research:

1. The samples of GC were too small. Only twenty-one patients with gastric cancers were included.

2. The study method is relatively simple, through sequencing genetic analysis to determine the correlation of GC treatment effects. No further verification was performed. The results are not very reliable.

3. The Table titles in this article are not standard, and Table 3 and 4 are not marked.  

NA

Author Response

The team of authors is grateful for the thorough review of the article. The proofreading of the article was carried out, it was analyzed and discussed once again. All modifications in the article are highlighted in the text.

Is there a potential bias in the selection of patients?

Response

Criteria for inclusion in the study: morphologically proven gastric cancer T2-4N0-3 (according to the TNM classification of the International Cancer Union 1980 - revision 2017); patients who had not previously received treatment; the general satisfactory condition of the patient, the age of patients is not older than 70 years (Karnovsky status is more than 60%, ECOG=0-1); consent patient for treatment; absence of synchronous and metachronous, malignant tumors.

Criteria for excluding patients from the study: the general serious condition of the patient-ECOG>2; patients with RV TLIONE1; patients who previously received any specific antitumor treatment for RV; patients with decompensated tumor stenosis of the antrum of the stomach, bleeding from the tumor, cachexia, perforation, dysphagia; refusal of the patient from treatment; the presence of distant metastases according to the data clinical examination, including laparoscopy (including Cy+ according to cytological examination of abdominal lavage); hypersensitivity to drugs. The effectiveness of treatment was assessed on the RECIST 1.1 scale.

Is the sample size (21 patients) sufficient to draw reliable conclusions? Considering the small number of patients, are the results statistically significant?

Response

Significant studies have been conducted to study universal markers of oncogenesis in patients with gastric cancer. It should be noted that these studies are preparatory and aim to substantiate the use of universal targeted markers for planning personalized treatment. In this group of patients, the dependence of the combined treatment effect with the use of standard treatment on the f key markers of targeted therapy was shown. The validity of statistical approaches for such a small group is related to the use of methods for the study of small groups.

Although no significant differences in total mutation number were found between HER2 and PD-L1 groups, the distribution of specific mutations varied. Do any hypotheses or data is suggesting potential interactions between these pathways that could explain this observation?

Response

It is absolutely true that the association between significant mutations and THEIR tumor status has not been revealed. However, the study showed a tendency associated with the prevalence of TP53 mutations with HER2 tumor status and the variation of mutations for PD-L1 status. tumors. The revealed data confirm the previously revealed facts about the involvement of multiple pathogenetic pathways in the development of gastric tumors. The text provides a link with the features of molecular markers in the tumor.

There are spelling errors, some are highlighted in the introduction on page 2 second paragraph" effeots", in materials and methods section "effectibeness". Please check for such errors.

Response

All mistakes were corrected.

Comments on the Quality of English Language

The English language needs to be improved and spell check is required.

Response

Proofreading was made.

Reviewer 2 Report

In the present study, the authors suggest that targeted gene mutations can influence both tumor characteristics and response to FLOT chemotherapy in GC patients. 

There are certain queries-

Is there a potential bias in the selection of patients?

Is the sample size (21 patients) sufficient to draw reliable conclusions? Considering the small number of patients, are the results statistically significant?

Although no significant differences in total mutation number were found between HER2 and PD-L1 groups, the distribution of specific mutations varied. Do any hypotheses or data is suggesting potential interactions between these pathways that could explain this observation?

There are spelling errors, some are highlighted in the introduction on page 2 second paragraph" effeots", in materials and methods section "effectibeness". Please check for such errors.

The English language needs to be improved and spell check is required.

Author Response

Response to the Reviewer 2

The team of authors is grateful for the thorough review of the article. The proofreading of the article was carried out, it was analyzed and discussed once again. All modifications in the article are highlighted in the text.

1. I just make sure are 21 GC patients are Russian? Prevalence of GC in Russia is very high according to Globocan. The readers, though, are not familiar with epidemiological or geographical information of GC in Russia. Please describe as an introduction on the GC in Russia. The authors cite TCGA or other international dataset, but GC is geographically very different in prevalence, etiology, and most importantly in handling.

Response

According to Globocan, the Russian Federation ranks fifth in the prevalence of gastric cancer in the world, with more than 37,000 new cases of malignant neoplasms detected in the Russian Federation in the group of both sexes aged 35 years and older. World statistics for 2020 show that gastric cancer is in sixth place, with the number of new cases of 1,075,176 people per year, which is 5.9% of the total number of cases of malignant neoplasms.

By ethnicity, all patients identified themselves as Russians living in the Tomsk region.Familial cases of stomach cancer are associated with early onset of the disease. There were no such cases in the conducted study. The average age of the patients was 57 years (from 40 to 70 years).

2. Among 21 cases, to me some cases look operable (compete resection with excellent prognosis). Is it not usual to operate GC in relatively earlier stage in Russia?

Response

The TNM stage for most of the parients was T3N0M0. It is no the early stage GC.

3. Non-tumor tissue had intestinal metaplasia?

Response

The non-transformed tissues had no intestinal metplasia. The diagnosis was verified be the two pathologists separately.

4. Please spell out first for FLOT (Fluorouracil, Leucovorin, oxaplatin, Docetaxel).

Response

The FLOT regimen was spelled in the text.

FLOT (fluorouracil, leucovorin, oxaliplatin, docetaxe) regimen

5. Just I wonder GC here is distal type or proximal type? 

Response

The cancers include adenocercinoma from the distal part of the stomach and its body

6. Any mutation spectrum for large consumption of Vodka?

Response

Dear, Reviewer, there are no reliable data on the influence of “Vodka” on any mutations.

Reviewer 3 Report

1. I just make sure are 21 GC patients are Russian? Prevalence of GC in Russia is very high according to Globocan. The readers, though, are not familiar with epidemiological or geographical information of GC in Russia. Please describe as an introduction on the GC in Russia. The authors cite TCGA or other international dataset, but GC is geographically very different in prevalence, etiology, and most importantly in handling.

2. Among 21 cases, to me some cases look operable (compete resection with excellent prognosis). Is it not usual to operate GC in relatively earlier stage in Russia?

3. Non-tumor tissue had intestinal metaplasia?

4. Please spell out first for FLOT (Fluorouracil, Leucovorin, oxaplatin, Docetaxel).

5. Just I wonder GC here is distal type or proximal type? 

6. Any mutation spectrum for large consumption of Vodka?

Author Response

Response to the Reviewer 3

The team of authors is grateful for the thorough review of the article. The proofreading of the article was carried out, it was analyzed and discussed once again. All modifications in the article are highlighted in the text.

1. The samples of GC were too small. Only twenty-one patients with gastric cancers were included.

Response

The investigation was too complex. The biopsy samples were included in to the study. It was really difficult to find enough DNA.

2. The study method is relatively simple, through sequencing genetic analysis to determine the correlation of GC treatment effects. No further verification was performed. The results are not very reliable.

Response

The preliminary study was first perfprmed . The additional study will include another verification markers

3. The Table titles in this article are not standard, and Table 3 and 4 are not marked

Response

All corrections were made

Round 2

Reviewer 1 Report

The authors basically responsed all the questions.

Author Response

The team of authors is grateful for the thorough review of the article. The proofreading of the article was carried out, it was analyzed and discussed once again. All modifications in the article are highlighted in the text.

The authors basically responsed all the questions.? There is a comment about the design research.

Response

The design of the research is done according the main idea of the paper. It could be improved in additional studies.

Reviewer 3 Report

This is very small numbers of the cases, but the information from understudied population would worth published with limitation remarks.

Author Response

The team of authors is grateful for the thorough review of the article. The proofreading of the article was carried out, it was analyzed and discussed once again. All modifications in the article are highlighted in the text.

This is very small numbers of the cases, but the information from understudied population would worth published with limitation remarks.

Response

The remarks about the number of cases were done in the text

GCs' availability of significant genetic markers does not have any impact on the effectiveness of combined treatment. Different mutation spectrums were observed, and patients with the absence of known oncogenic markers showed the best response to treatment and complete regression. The biological properties of tumors can be altered by significant genetic markers, which can affect the effectiveness of antitumor treatment. Predicting personalized therapy depends on IH tumor status, but research has confirmed the association of HER2 with TP53 mutation, as well as the immunoheterogeneity of the tumor with PD-L1 status and high mutational diversity. The revealed facts are preliminary and require further confirmation.