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Wu et al. J Cancer Metastasis Treat 2020;6:40 I http://dx.doi.org/10.20517/2394-4722.2020.77 Page 7 of 9

extra use of steroids and cessation of nivolumab certainly further contributed to his disease progression.
Consequently, understanding the correlation between skin irAEs and clinical outcome could provide
valuable information in distinguishing between pseudo-progression and immunotherapy resistance, which
will assist oncologists in the decision of resuming immunotherapy after the recovery from manageable skin
irAEs.

The mechanism of immunotherapy induced BP is currently unclear. While BP is associated with both a
humoral and a cellular response, it is widely believed that immunotherapy induced BP could be provoked
by an autoantibody targeted to a sharedantigen and the dysfunction in T-regulatory cells, which is inhibited
[23]
by immunotherapy . The shared target antigen is located both at the dermoepidermal junction and on
the surface of tumour cells, such as BP 180, whichcan be expressed on the surface of melanoma cells, non-
small cell lung cancer cells and basement membrane skin cancer [24,25] . Meanwhile, dysregulation of PD-1/
PD-L1 and CTLA-4 signal pathway induced by immunotherapy can impair the balance within the immune
[26]
system, resulting in the development of off-target effects and autoimmunity . Further studies are required
to determine the underlying mechanisms of immunotherapy induced BP.

Conclusion
Here, we report a rare case of severe, extensive and refractory nivolumab-induced BP in a patient with
advanced renal cancer. With the widespread use of immunotherapy, it has become increasingly important
to document cases of immunotherapy-induced BP to provide more information in diagnosing and treating
these cutaneous adverse events. Moreover, the close collaboration between dermatologists and oncologists
is essential to allow the patients with cutaneous irAEs to continue antitumor therapy, avoiding unnecessary
discontinuation of immunotherapy.

DECLARATIONS
Acknowledgments
All authors would like to acknowledge Dr. Dalila Malek, Dr. Paul Gatt, Dr. Ravi Suchak and Dr. Marice
Sudaerson (Southend Hospital) for support and advice.

Authors’ contributions
Designed the study and wrote the manuscript: Wu X, Palvai S
Reviewed and approved the manuscript: Jalil A

Availability of data and materials
Not applicable.

Financial support and sponsorship
This study support by National Health Service Funding.

Conflicts of interest
All authors declared that there are no conflicts of interest.

Ethical approval and consent to participate
Written informed consent was obtained from the patient.

Consent for publication
Written informed consent was obtained from the patient for publication of this case report and any
companying images.