Digital Papillary Adenocarcinoma: The Detection of Low-Risk Human Papillomaviruses and the BRAF p.V600E Mutation in a Subset of Cases
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
After the recent detection of HPV42 in digital papillary adenocarcinoma and the controversial finding of rare BRAF mutations, the autjors present their experience using LR-HPV ISH and BRAF IHC.
The study is of interest and the manuscript is well-written and illustrated.
My only significant concern regards case selection. For the findings to be solid and robust the authors need to list inclusion and exclusion criteria for the diagnosis of digital papillary adenocarcinoma and how these tumors are separated form hidradenoma, hidradenocarcinoma, cystadenoma and tubular adenoma.
The authors mention the value of IHC for this purpose. It would strengthen the authors' argument, if all tumors were worked up for S100, SOX10, p40/p63 and SMA by IHC.
The authors mention a recent study in which BRAF mutations were seen in a subset of digital papillary adenocarcinoma (ref 14). This is problematic ans the diagnosis of at leas t some of the tumors is in doubt. The authors need to discuss this in the context of the subsequent letter (Kervarrec T, Busam KJ. Acral BRAF-mutated tubular adenoma should be distinguished from HPV42-related digital papillary adenocarcinoma. J Cutan Pathol. 2023 Jun;50(6):577-579. doi: 10.1111/cup.14430. Epub 2023 Apr 14. PMID: 37057379.).
The authors also need to provide prove that the diagnosis for their patient 13 is correct. The provided image certainly resembles tubular adenoma.
The rate of LR-HPH and BRAF negative cases is very high compared to the recent literature. This requires further discussion. The authors also need to prove that these tumors represent examples of digital papillary adenocarcinoma. The tumor presented in panes A of Fig 1 certainly resembles hidradenoma/hidradenocarcinoma rather than digital papillary adenocarcinoma.
Using LR-HPV ISH instead of HPV42 ISH is a minor shortcoming of this series.
Author Response
Response to reviewer #1’s comments and suggestions for authors
After the recent detection of HPV42 in digital papillary adenocarcinoma and the controversial finding of rare BRAF mutations, the authors present their experience using LR-HPV ISH and BRAF IHC.
The study is of interest and the manuscript is well-written and illustrated.
We thank the reviewer #1 for this kind comment.
My only significant concern regards case selection. For the findings to be solid and robust the authors need to list inclusion and exclusion criteria for the diagnosis of digital papillary adenocarcinoma and how these tumors are separated form hidradenoma, hidradenocarcinoma, cystadenoma and tubular adenoma.
The authors mention the value of IHC for this purpose. It would strengthen the authors' argument, if all tumors were worked up for S100, SOX10, p40/p63 and SMA by IHC.
We agree with the reviewer’s comments regarding the diagnosis of the cases included in this study since the diagnosis of DPA can be challenging especially in small/ limited biopsies to differentiate from its mimickers.
In 8 of 13 cases included in this study, a panel of immunohistochemical studies was indeed used during the diagnostic work up. Due to inadequacy or unavailability of additional materials, full panel of immunohistochemical studies was not performed in the 5 remaining cases. However, the cases were extensively reviewed and discussed in our dermatopathology consensus meeting together with seven board certified dermatopathologists with special expertise in skin tumors; each of the DPA included in this study exhibited histologic features supporting the diagnosis.
The authors mention a recent study in which BRAF mutations were seen in a subset of digital papillary adenocarcinoma (ref 14). This is problematic as the diagnosis of at least some of the tumors is in doubt. The authors need to discuss this in the context of the subsequent letter (Kervarrec T, Busam KJ. Acral BRAF-mutated tubular adenoma should be distinguished from HPV42-related digital papillary adenocarcinoma. J Cutan Pathol. 2023 Jun;50(6):577-579. doi: 10.1111/cup.14430. Epub 2023 Apr 14. PMID: 37057379.).
Thanks for pointing this out. Since the association of BRAF with tubular adenoma and/or DPA is still controversial in the literature, as we discussed in our manuscript, we believe that more studies with larger sample size is required to confirm the reported findings.
The authors also need to provide prove that the diagnosis for their patient 13 is correct. The provided image certainly resembles tubular adenoma.
Thanks again. Please kindly see our response above regarding usage of a panel of immunohistochemical studies and consensus diagnosis among 7 board certified dermatopathologists.
The rate of LR-HPH and BRAF negative cases is very high compared to the recent literature. This requires further discussion. The authors also need to prove that these tumors represent examples of digital papillary adenocarcinoma. The tumor presented in panes A of Fig 1 certainly resembles hidradenoma/hidradenocarcinoma rather than digital papillary adenocarcinoma.
Using LR-HPV ISH instead of HPV42 ISH is a minor shortcoming of this series.
We agree that using LR-HPV ISH instead of HPV42 ISH is a minor shortcoming. Had it been available to us in a CLIA-approved setting, we would’ve preferred using HPV42 ISH it in addition to LR-HPV ISH. Therefore, in our opinion, evaluating the utility of a CLIA-approved test that is widely available is likely to have immediate diagnostic possibility, compared to HPV42 ISH.
Reviewer 2 Report
Comments and Suggestions for Authors
The authors report the results of a study analyzing the presence of low-risk HPV and BRAF p.V600E. by in situ hybridization and immunohistochemistry, respectively, In 13 cases of digital papillary adenocarcinoma (DPA) and 3 cases of acral hidradenoma (AH).
Comments:
(1) The term “association with” usually implies a frequent presence of a virus or a genetic alteration in a neoplasm. In this series, however, only one out of 13 DPA cases was positive for BRAF p.V600E. Moreover, the authors state on page 6 that this case may in fact represent a tubular adenoma. These data in fact demonstrates that DPA is not associated with BRAF. In addition, only less than half of the 13 DPA cases harbored LR-HPV. Thus, the title of the manuscript is misleading and needs to be changed, e.g.:“Digital Papillary Adenocarcinoma: Detection of Low-risk 2 Human Papillomaviruses and BRAF p.V600E mutation in a subset of cases”.
(2) A very small number of only 3 cases of acral hidradenoma (AH) was investigated for LR-HPV and BRAF . Therefore, the value of LR-HPV and BRAF positivity in DPA for the distinction from AH cannot be adequately assessed. As a consequence, the sentence “Though our sample size is limited, our findings indicate that LR-HPV 19 by ISH may aid in diagnosing DPA and distinguishing it from acral hidradenoma” needs to be modified or omitted. A potential modification could be: “Larger studies are needed to assess the value of detecting LR-HPV and BRAF p.V600E in the distinction of DPA form AH”.
(3) ISH may not be sensitive enough to detect LR-HPV. It would be useful to compare the detection of LR-HPV by ISH with PCR as a more sensitive diagnostic tool.
Author Response
(1) The term “association with” usually implies a frequent presence of a virus or a genetic alteration in a neoplasm. In this series, however, only one out of 13 DPA cases was positive for BRAF p.V600E. Moreover, the authors state on page 6 that this case may in fact represent a tubular adenoma. These data in fact demonstrates that DPA is not associated with BRAF. In addition, only less than half of the 13 DPA cases harbored LR-HPV. Thus, the title of the manuscript is misleading and needs to be changed, e.g.:“Digital Papillary Adenocarcinoma: Detection of Low-risk Human Papillomaviruses and BRAF p.V600E mutation in a subset of cases”.
We thank the reviewer for their comments and have made changes to the title accordingly.
(2) A very small number of only 3 cases of acral hidradenoma (AH) was investigated for LR-HPV and BRAF . Therefore, the value of LR-HPV and BRAF positivity in DPA for the distinction from AH cannot be adequately assessed. As a consequence, the sentence “Though our sample size is limited, our findings indicate that LR-HPV 19 by ISH may aid in diagnosing DPA and distinguishing it from acral hidradenoma” needs to be modified or omitted. A potential modification could be: “Larger studies are needed to assess the value of detecting LR-HPV and BRAF p.V600E in the distinction of DPA form AH”.
We thank the reviewer for their comments and have made changes to this sentence accordingly.
(3) ISH may not be sensitive enough to detect LR-HPV. It would be useful to compare the detection of LR-HPV by ISH with PCR as a more sensitive diagnostic tool.
We thank the reviewer for their comments and have made edits in the discussion accordingly.
Reviewer 3 Report
Comments and Suggestions for Authors
Ultimately, this was an archived study and the preliminary diagnosis linked with hidradenoma is a crucial aspect and whether the use LR-HPV will reveal cases that need the diagnosis to be revised. The negative results with wild types diminish the significance of the study. The authors have stated this aspect particularly in their concluding paragraph.
Meanwhile, I discovered aspects that the authors may wish to modify -particularly the inclusion of acral hidradenomas as an unnecessary control particularly as the adenomatous aspect of digital papillary adenocarcinoma is a pitfall. The negative in this group only adds to the pitfall in this cohort as the outcomes in the study were not predicted by the probes. However the authors do allude to this conclusion and therefore is not a major issue. In my opinion, this still represents an excellent study requiring relatively minor revision.
Author Response
We thank the reviewer #2 for this kind comment. Regarding with the limitation of including hidradenomas in this study, as the reviewer noticed, we have included in this discussion of the manuscript.
Round 2
Reviewer 1 Report
Comments and Suggestions for Authors
Unfortunately the authors did not address my main concern regarding tissue selection. Their findings contradict recent studies on this topic and it would therefore be prudent to obtain more objective parameters to confirm the diagnosis of the tumors presented here. Consensus diagnosis of 7 board certified dermatopathologists is highly subjective and insufficient for a scientific study.
I seriously doubt that there is a true association between BRAF and digital papillary adenocarcinoma. Case 13 illustrated here does not look like an example of digital papillary adenocarcinoma to me and it should not be included. Similarly the illustrated case 3 resembles hidradenoma or hidradenocarcinoma at least from the supplied image, which would explain the absence of BRAF and LR HPV staining.
Given the uncertainty of the diagnoses, the title needs to be changed.
There is a duplication in the reference list.
The table lists the tumors as digital papillary adenoma. This is incorrect
Author Response
Unfortunately the authors did not address my main concern regarding tissue selection. Their findings contradict recent studies on this topic and it would therefore be prudent to obtain more objective parameters to confirm the diagnosis of the tumors presented here. Consensus diagnosis of 7 board certified dermatopathologists is highly subjective and insufficient for a scientific study.
I seriously doubt that there is a true association between BRAF and digital papillary adenocarcinoma. Case 13 illustrated here does not look like an example of digital papillary adenocarcinoma to me and it should not be included. Similarly the illustrated case 3 resembles hidradenoma or hidradenocarcinoma at least from the supplied image, which would explain the absence of BRAF and LR HPV staining.
Given the uncertainty of the diagnoses, the title needs to be changed.
We thank the reviewer for their comments and have changed the title accordingly.
There is a duplication in the reference list.
The table lists the tumors as digital papillary adenoma. This is incorrect.
We thank the reviewer for their suggestions and have corrected the duplication citation and table.
Reviewer 2 Report
Comments and Suggestions for Authors
The authors have addressed the reviewer's comments in the revised version.
I have only one comment: The meaning of the sentence on lines 136-137 is not clear in its current form. Thus I would propose to change this sentence to: "Additionally, further studies comparing the detection of LR-HPV using ISH versus polymerase chain reaction (PCR) can help assessing the value of ISH as a diagnostic tool.
Author Response
We thank the reviewer for their comments and have changed the sentence accordingly.
