Invasive squamous cell carcinoma: comparison of differentiation grade and tumour depth by anatomical site in 1666 tumours

MicroRNA Signatures Associated with Basal Cell Carcinoma Subtypes

Basal cell carcinoma (BCC) is classified histologically into subtypes that determine treatment decisions. MicroRNAs (miRs) are short noncoding RNAs that may serve as diagnostic biomarkers. We investigated if particular miRs could distinguish BCC subtypes. We sequenced miRs from 55 archival BCC and 9 control skin specimens and then validated these miRs by qRT-PCR assay on a second BCC cohort (18 superficial, 16 nodular, 15 infiltrative) and control skin (n = 12). Expression values for individual miRs were normalized to miR-16-5p, which was the least variant among the control skin and BCC samples. We found that (i) miR-383-5p and miR-145-5p are downregulated in all BCC subtypes compared with control skin, (ii) miR-181c-5p is downregulated in superficial compared with invasive (nodular/infiltrative) BCC, and (iii) miR-22-5p and miR-708-5p are upregulated in infiltrative compared with superficial/nodular BCC and miR-30c-5p is downregulated in infiltrative compared with nodular BCC. Receiver operating characteristic analysis demonstrated excellent capacity of these miRs to discriminate between BCC and control skin (area under the curve, 0.94-0.98), whereas the capacity to discriminate between superficial and invasive subtypes was less robust (area under the curve, 0.7-0.8). Future prospective studies may determine the utility of these miRs as diagnostic biomarkers to guide biopsy and treatment of BCC.

Sex Disparity for Patients with Cutaneous Squamous Cell Carcinoma of the Head and Neck: A Systematic Review

The incidence of head and neck cutaneous squamous cell carcinoma (HNcSCC) is unevenly distributed between men and women. At present, the mechanism behind this disparity remains elusive. This study conducted a systematic review and meta-analysis of proportions to investigate the disparity between sexes for patients with HNcSCC. PubMed, Scopus, EMBASE, MEDLINE, Emcare and CINAHL were searched in November 2021 and June 2022 (N > 50, English, human), and studies which examined the association between sex and HNcSCC were included. Analysis was conducted using RStudio with data and forest plots displaying males as a proportion of total patients with HNcSCC. Two independent researchers performed study selection, data extraction, data analysis and risk of bias. Eighty-two studies (1948 to 2018) comprising approximately 186,000 participants (67% male, 33% female) from 29 countries were included. Significantly more males had HNcSCC overall (71%; CI: 67−74). Males were also significantly more affected by cSCC of the ear (92%; CI: 89−94), lip (74%; CI: 66−81), and eyelid (56%; CI: 51−62). This study found HNcSCC disproportionately affected males overall and across all subtypes. Improving our understanding of sex-specific mechanisms in HNcSCC will better inform our preventive, therapeutic and prognostic practices.

Consistent downregulation of the cleft lip/palate-associated genes IRF6 and GRHL3 in carcinomas

Interferon Regulatory Factor 6 (IRF6) and Grainyhead Like Transcription Factor 3 (GRHL3) are transcription factors that orchestrate gene regulatory networks required for the balance between keratinocyte differentiation and proliferation. Absence of either protein results in the lack of a normal stratified epidermis with keratinocytes failing to stop proliferating and to terminally differentiate. Numerous pathological variants within IRF6 and GRHL3 have been identified in orofacial cleft-affected individuals and expression of the two transcription factors has been found to be often dysregulated in cancers. However, whether orofacial cleft-associated IRF6 and GRHL3 variants in patients might also affect their cancer risk later in life, is not clear yet. The fact that the role of IRF6 and GRHL3 in cancer remains controversial makes this question even more challenging. Some studies identified IRF6 and GRHL3 as oncogenes, while others could attribute tumor suppressive functions to them. Trying to solve this apparent conundrum, we herein aimed to characterize IRF6 and GRHL3 function in various types of carcinomas. We screened multiple cancer and normal cell lines for their expression, and subsequently proceeded with functional assays in cancer cell lines. Our data uncovered consistent downregulation of IRF6 and GRHL3 in all types of carcinomas analyzed. Reduced levels of IRF6 and GRHL3 were found to be associated with several tumorigenic properties, such as enhanced cell proliferation, epithelial mesenchymal transition, migration and reduced differentiation capacity. Based on our findings, IRF6 and GRHL3 can be considered as tumor suppressor genes in various carcinomas, which makes them potential common etiological factors for cancer and CLP in a fraction of CLP-affected patients.

Actinic keratoses contiguous with squamous cell carcinomas are mostly non-hyperkeratotic and with severe dysplasia

AIMS

Actinic keratosis (AK) is a precursor of cutaneous squamous cell carcinoma (SCC). No validated parameters can predict which AKs will progress into SCCs, but especially thick AKs are under suspicion. The clinical and histopathological thickness of AKs is strongly correlated. This study aimed to investigate the thicknesses and degree of dysplasia of AKs contiguous with SCCs assuming these AKs represent the AKs that have undergone malignant transformation.

METHODS

Files of the Pathology Department, Hospital of Southern Jutland, Denmark, were reviewed. 111 cases met the inclusion criteria: a skin biopsy containing an invasive SCC. All SCCs merged with an AK at the edge. Degree of dysplasia, epidermal thickness and stratum corneum thicknesses of AKs were measured.

RESULTS

All AKs showed severe dysplasia. Most AKs had a stratum corneum thickness under 0.1 mm and an epidermal thickness under 0.5 mm, corresponding to clinically thin and non-hyperkeratotic AKs.

CONCLUSIONS

Our result suggests malignant progression potential of AKs regardless of thickness.

Early Squamous Cell Carcinoma With Perineural Invasion: A Prospective Study Examining Anatomic Site, Tumor Surface Diameter, Invasion Depth, and Grade of Differentiation in 1,772 Consecutive Cases

Background

Squamous cell carcinoma (SCC) may present with perineural invasion (PNI).

Objective

To investigate the characteristics of early invasive SCC with or without PNI.

Methods

Consecutive SCC excisions were prospectively reviewed from a single Australian community-based practice for 2016-2018. Tumor characteristics recorded were anatomic site, maximum microscopic tumor surface diameter, invasion depth, grade of differentiation, and diameter of nerves with PNI.

Results

In total, 1,772 cases were collected. No PNI cases were found on female patients. Seven of the total 10 PNI cases were on facial sites. Maximum average microscopic tumor surface diameters ranged from 10.1 mm (well differentiated) up to 11.0 mm (moderately differentiated). Maximum average invasion depths by differentiation ranged from 1.7 (well differentiated) up to 2.6 mm (poorly differentiated). The PNI cases were as follows: well differentiated (n = 0), moderately differentiated (n = 4), or poorly differentiated (n = 6). Minimum average histopathological margins for well, moderately, and poorly differentiated SCC, respectively, were 1.4, 1.1, and 1.3 mm. Minimum microscopic tumor surface diameters for PNI cases were 7 mm for moderately and 5 mm for poorly differentiated SCC. Minimum microscopic invasion depths for PNI cases were 2.2 mm for moderate and 0.9 mm for poor differentiation.

Conclusions

We found early SCC with PNI displayed nerve diameters of 0.1 mm or less and were exclusively on male patients aged 60 or older, on chronically sun-exposed sites of the head and upper midline anterior chest. Histopathological features associated with PNI were moderate and poor differentiation, tumor invasion beyond 0.9 mm, and adjacent lymphocytosis.

Poorly differentiated cutaneous squamous cell carcinomas have high incomplete excision rates with UK minimum recommended pre-determined surgical margins

BACKGROUND

In the UK, the British Association of Dermatology-British Association of Plastic, Reconstructive and Aesthetic Surgery (BAD-BAPRAS) guidelines recommend excision of high-risk cutaneous squamous cell carcinomas (cSCCs), including poorly differentiated cSCCs, with a minimum peripheral margin of 6 mm¹.

OBJECTIVES

We assess whether the BAD-BAPRAS minimum margin achieves histological clearance in poorly differentiated cSCCs.

PATIENTS AND METHODS

Demographics, surgical notes and histological reports from all patients having a primary cSCC excised at the Plastic Surgery Department of Addenbrooke's Hospital, Cambridge, UK, between January 2017 and April 2018 were analysed. Ordinal regression was performed for excision margin status versus histological grade by using size and site as co-variates.

RESULTS

Of 296 cSCCs, 38(12.8%) were poorly differentiated. Patients with poorly differentiated cSCCs were older (81.1 years vs. 76.7 years, p = 0.038), had lesions on the face or scalp (89.2% vs. 52.1%, p = 0.0001), and had lymphovascular (10.5% vs. 0%, p = 0.001) or perineural invasion (15.8% vs. 2%, p = 0.002). Well-differentiated cSCCs were excised with an average peripheral margin of 4.72 mm (95% CI 4.25-5.18 mm), while poorly differentiated cSCCs were excised with a margin of 6.42 mm(95% CI 5.58-7.28 mm). Close or involved peripheral margins were seen in 3% of well-differentiated lesions but in 13.2% of poorly differentiated lesions (OR=45.02; p = 0.003). Deep margins were close in 13.1% (none involved) of well-differentiated lesions but close or involved in 50% of poorly differentiated lesions (OR=11.94; p = 0.001).

CONCLUSIONS

We demonstrate that poorly differentiated cSCCs are frequently incompletely excised in both peripheral and deep planes, despite adherence to guidelines. The UK BAD-BAPRAS guidelines should be urgently updated in line with international consensus.