Identification of proteins associated with development of metastasis from cutaneous squamous cell carcinomas (cSCCs) via proteomic analysis of primary cSCCs*

Abstract

Summary Background Cutaneous squamous cell carcinoma (cSCC) is one of the most common cancers capable of metastasizing. Proteomic analysis of cSCCs can provide insight into the biological processes responsible for metastasis, as well as future therapeutic targets and prognostic biomarkers. Objectives To identify proteins associated with development of metastasis in cSCC. Methods A proteomic‐based approach was employed on 105 completely excised, primary cSCCs, comprising 52 that had metastasized (P‐M) and 53 that had not metastasized at 5 years post‐surgery (P‐NM). Formalin‐fixed, paraffin‐embedded cSCCs were microdissected and subjected to proteomic profiling after one‐dimensional (1D), and separately two‐dimensional (2D), liquid chromatography fractionation. Results A discovery set of 24 P‐Ms and 24 P‐NMs showed 144 significantly differentially expressed proteins, including 33 proteins identified via both 1D and 2D separation, between P‐Ms and P‐NMs. Several differentially expressed proteins were also associated with survival in SCCs of other organs. The findings were verified by multiple reaction monitoring on six peptides from two proteins, annexin A5 (ANXA5) and dolichyl‐diphosphooligosaccharide–protein glycosyltransferase noncatalytic subunit (DDOST), in the discovery group and validated on a separate cohort (n = 57). Increased expression of ANXA5 and DDOST was associated with reduced time to metastasis in cSCC and decreased survival in cervical and oropharyngeal cancer. A prediction model using ANXA5 and DDOST had an area under the curve of 0·93 (confidence interval 0·83–1·00), an accuracy of 91·2% and higher sensitivity and specificity than cSCC staging systems currently in clinical use. Conclusions This study highlights that increased expression of two proteins, ANXA5 and DDOST, is significantly associated with poorer clinical outcomes in cSCC.

Proteomic Profiling of Archived Tissue of Primary Melanoma Identifies Proteins Associated with Metastasis

“…It is recognised that the immune system plays an important role in tumorigenesis and cancer metastases, including in skin cancer [38,39]. Indeed, it has been shown that immunosuppressed individuals have an increased risk of developing melanoma [40], and that immunosuppressed individuals are at much greater risk of developing metastasis than immunocompetent individuals [41].…”

The Multidisciplinary Management of Cutaneous Squamous Cell Carcinoma: A Comprehensive Review and Clinical Recommendations by a Panel of Experts

“…In an analysis of 48 RNA samples, despite the small sample size, several microRNAs were found to show differential expression between primary tumors which metastasized and those that did not [ 28 ]. Finally, in a proteomic-based study including 105 CSCC samples, half of which metastasized within 5 years from surgery, increased expression of two proteins, ANXA5 and DDOST, was significantly associated with development of metastasis, highlighting the potential role of proteomic analysis into risk stratification of patients with CSCC [ 29 ]. However, as of today, the impact of molecular and epigenetic characterization on prognosis and targeted treatments is not entirely clear, and it should not be routinely performed in everyday clinical practice, outside of translational studies ( expert recommendation 4 ).…”

Unpicking the Gordian knot of identifying metastasis development‐relevant proteins in cutaneous squamous cell carcinoma

“…It may be surprising to many readers that an analysis of the proteins expressed in primary cSCC that are associated with metastasis (or indeed clinical outcomes) has not been reported previously. So, in this regard, the study by Shapanis et al 5 . is particularly important and timely.…”

“…It may be surprising to many readers that an analysis of the proteins expressed in primary cSCC that are associated with metastasis (or indeed clinical outcomes) has not been reported previously. So, in this regard, the study by Shapanis et al 5 is particularly important and timely. Moreover, this study is innovative as it deployed a combination of proteomics, machine learning and mathematical modelling to identify key prognostic indicators in cSCC.…”

“…The study in this issue of the BJD by Shapanis et al ., 5 from the Healy and Skipp laboratories in Southampton, asked the very pertinent question of whether cSCC tumour protein profiles differ in those primary tumours that do and those that do not metastasize within 5 years following the primary tumour excision. It may be surprising to many readers that an analysis of the proteins expressed in primary cSCC that are associated with metastasis (or indeed clinical outcomes) has not been reported previously.…”