CKS1B amplification is a frequent event in cutaneous squamous cell carcinoma with aggressive clinical behaviour

Increased Risk of Local Recurrence in Cutaneous Squamous Cell Carcinoma Arising in Sun-Exposed Skin: A Retrospective Cohort Study

BACKGROUND

The incidence of cutaneous squamous cell carcinoma (cSCC) is increasing over the years. Risk factors for local recurrence and metastasis have been widely studied in highly sun-exposed areas of the body but less data exist about less sun-exposed ones. The main objective of this study is to compare the risk of local recurrence and metastases in patients with cSCC in highly sun-exposed areas compared to cSCC in less sun-exposed areas.

MATERIAL AND METHODS

A retrospective observational study was carried out, including 558 patients with histopathologically confirmed cSCC at the Reina Sofía University Hospital (HURS), Córdoba, during the period from 1 January 2017 to 31 December 2020. Demographic, clinical and anatomopathological data were collected.

RESULTS

Local recurrence occurs more often in highly sun-exposed areas (15.8%) compared to less sun-exposed ones (7.4%) (p < 0.05). However, no differences in the rate of metastases in both groups were found. The presence of affected surgical margins and tumor thickness were identified as independent risk factors for cSCC in low sun-exposure areas.

CONCLUSIONS

cSCC located in anatomical areas of high sun exposure presented a greater risk of developing local recurrence in our population, which could suggest that these tumors have worse prognosis than those that lie in areas that do not receive chronic sun exposure.

The genomic landscape of cutaneous SCC reveals drivers and a novel azathioprine associated mutational signature

Cutaneous squamous cell carcinoma (cSCC) has a high tumour mutational burden (50 mutations per megabase DNA pair). Here, we combine whole-exome analyses from 40 primary cSCC tumours, comprising 20 well-differentiated and 20 moderately/poorly differentiated tumours, with accompanying clinical data from a longitudinal study of immunosuppressed and immunocompetent patients and integrate this analysis with independent gene expression studies. We identify commonly mutated genes, copy number changes and altered pathways and processes. Comparisons with tumour differentiation status suggest events which may drive disease progression. Mutational signature analysis reveals the presence of a novel signature (signature 32), whose incidence correlates with chronic exposure to the immunosuppressive drug azathioprine. Characterisation of a panel of 15 cSCC tumour-derived cell lines reveals that they accurately reflect the mutational signatures and genomic alterations of primary tumours and provide a valuable resource for the validation of tumour drivers and therapeutic targets.

Cross-species identification of genomic drivers of squamous cell carcinoma development across preneoplastic intermediates

Cutaneous squamous cell carcinoma (cuSCC) comprises 15-20% of all skin cancers, accounting for over 700,000 cases in USA annually. Most cuSCC arise in association with a distinct precancerous lesion, the actinic keratosis (AK). To identify potential targets for molecularly targeted chemoprevention, here we perform integrated cross-species genomic analysis of cuSCC development through the preneoplastic AK stage using matched human samples and a solar ultraviolet radiation-driven Hairless mouse model. We identify the major transcriptional drivers of this progression sequence, showing that the key genomic changes in cuSCC development occur in the normal skin to AK transition. Our data validate the use of this ultraviolet radiation-driven mouse cuSCC model for cross-species analysis and demonstrate that cuSCC bears deep molecular similarities to multiple carcinogen-driven SCCs from diverse sites, suggesting that cuSCC may serve as an effective, accessible model for multiple SCC types and that common treatment and prevention strategies may be feasible.

Active nuclear IKK correlates with metastatic risk in cutaneous squamous cell carcinoma

About 5% of all cutaneous squamous cell carcinomas (cSCCs) metastasize, which is the principal cause of death by this type of cancer. However, to date there are no reliable biomarkers that categorize those SCC patients that will progress to metastasis. Nuclear active IKKα diminishes Maspin levels in prostate cancer facilitating its metastatic potential. In this paper, we describe the immunohistochemical analysis of active IKK and Maspin in 56 metastasizing and 51 non-metastasizing primary cSCC to measure their association with cancer behaviour. We also determined the effect of inhibiting IKK activity in SCC cell growth and migration in vitro. We found that high levels of nuclear active IKK in the primary tumour are predictive of cSCC metastatic capacity, in particular when combined with poor tumour differentiation and a history of tumour recurrence. Active IKK inversely correlated with Maspin levels in cSCC tumours, and samples negative for Maspin are exclusively found in the metastatic group. Mechanistically, IKK activity regulates cellular motility and SCC cell survival. Our results indicate that nuclear active IKK is a robust biomarker to predict cSCC outcome, and suggest the possibility of targeting IKK activity as a future therapy for treating metastatic cSCC.

Identification of multiple DNA copy number alterations including frequent 8p11.22 amplification in conjunctival squamous cell carcinoma

PURPOSE

Little is known about the molecular alterations that drive formation and growth of conjunctival squamous cell carcinoma (cSCC). We therefore sought to identify genetic changes that could be used as diagnostic markers or therapeutic targets.

METHODS

The DNA extracted from 10 snap-frozen cSCC tumor specimens and 2 in situ carcinomas was analyzed using array-based comparative genomic hybridization (aCGH), and further examined with NanoString and quantitative PCR.

RESULTS

The number of regions of DNA loss ranged from 1 to 23 per tumor, whereas gains and amplifications ranged from 1 to 15 per tumor. Most large regions of chromosomal gain and loss were confirmed by NanoString karyotype analysis. The commonest alteration was amplification of 8p11.22 in 9 tumors (75%), and quantitative PCR analysis revealed 100-fold or greater overexpression of ADAM3A mRNA from 8p11.22 locus. In addition, recurring losses were observed at 14q13.2 and 22q11.23, both lost in 5 (42%) of the 12 tumors, and at 12p13.31, lost in 4 (33%) of the 12 samples. Of the eight loci associated with the DNA damage repair syndrome xeroderma pigmentosum, three showed loss of at least one allele in our aCGH analysis, including XPA (9q22.33, one tumor), XPE/DDB2 (11p11.2, one tumor) and XPG/ERCC5 (13q33.1, three tumors).

CONCLUSIONS

Conjunctival SCC contains a range of chromosomal alterations potentially important in tumor formation and growth. Amplification of 8p11.22 and overexpression of ADAM3A suggests a potential role for this protease. Our findings also suggest that defects in DNA repair loci are important in sporadic cSCC.

Oncogenic function of SCCRO5/DCUN1D5 requires its Neddylation E3 activity and nuclear localization

PURPOSE

To determine mechanisms by which SCCRO5 (aka DCUN1D5) promotes oncogenesis.

EXPERIMENTAL DESIGN

SCCRO5 mRNA and protein expression were assessed in 203 randomly selected primary cancer tissue samples, matched histologically normal tissues, and cell lines by use of real-time PCR and Western blot analysis. SCCRO5 overexpression was correlated with survival. The effect of SCCRO5 knockdown on viability was assessed in selected cancer cell lines. Structure-function studies were performed to determine the SCCRO5 residues required for binding to the neddylation components, for neddylation-promoting activity, and for transformation.

RESULTS

In oral and lung squamous cell carcinomas, SCCRO5 mRNA levels corresponded with protein levels and overexpression correlated with decreased disease-specific survival. Knockdown of SCCRO5 by RNAi resulted in a selective decrease in the viability of cancer cells with high endogenous levels, suggesting the presence of oncogene addiction. SCCRO5 promoted cullin neddylation while maintaining conserved reaction processivity paradigms involved in ubiquitin and ubiquitin-like protein conjugation, establishing it as a component of the neddylation E3. Neddylation activities in vitro required the potentiating of neddylation (PONY) domain but not the nuclear localization sequence (NLS) domain. In contrast, both the NLS domain and the PONY domain were required for transformation of NIH-3T3 cells.

CONCLUSIONS

Our data suggest that SCCRO5 has oncogenic potential that requires its function as a component of the neddylation E3. Neddylation activity and nuclear localization of SCCRO5 are important for its in vivo function.

Cutaneous squamous cell carcinoma: defining the high-risk variant

With a lifetime incidence of approximately 10% in the general population, cutaneous squamous cell carcinoma (CSCC) is the second most common type of nonmelanoma skin cancer. Most CSCCs are benign and can be completely eradicated by surgery or other dermatological procedures. There is, however, a subgroup associated with an increased likelihood of lymph node metastases and, therefore, with high morbidity and mortality. This article analyzes the various factors that define aggressive CSCC. We propose a method for defining high-risk SCC on the basis of a series of major and minor criteria. This method will allow better prognostic evaluation and enable personalized management of patients with high-risk SCC, possibly leading to improved overall survival.

Cks1: Structure, Emerging Roles and Implications in Multiple Cancers

Deregulation of the cell cycle results in loss of normal control mechanisms that prevent aberrant cell proliferation and cancer progression. Regulation of the cell cycle is a highly complex process with many layers of control. One of these mechanisms involves timely degradation of CDK inhibitors (CKIs) like p27^Kip1 by the ubiquitin proteasomal system (UPS). Cks1 is a 9 kDa protein which is frequently overexpressed in different tumor subtypes, and has pleiotropic roles in cell cycle progression, many of which remain to be fully characterized. One well characterized molecular role of Cks1 is that of an essential adaptor that regulates p27^Kip1 abundance by facilitating its interaction with the SCF-Skp2 E3 ligase which appends ubiquitin to p27^Kip1 and targets it for degradation through the UPS. In addition, emerging research has uncovered p27^Kip1-independent roles of Cks1 which have provided crucial insights into how it may be involved in cancer progression. We review here the structural features of Cks1 and their functional implications, and also some recently identified Cks1 roles and their involvement in breast and other cancers.