Background: Actinic keratosis (AK) is one of the most common lesions on chronically sun-damaged skin that has the risk of progression to invasive squamous cell carcinoma (SCC). With the possibilities of using digital technologies for following-up skin lesions and their increased use in the past few decades, our objective was to update the review by Quaedvlieg et al., 2006, and to review prospective studies from 2005 onwards to identify the clinical characteristics of AK that later progressed to SCC. Methods: The PubMed, Scopus, and ScienceDirect databases were searched for relevant articles. The search had the following criteria: English language, human subjects and year from 2005 onwards. The study protocol was registered in the Prospero database with the record number CRD42020200429 and followed the PRISMA guidelines. The risk-of-bias assessment was performed using the QUIPS tool. Results: From the 5361 studies screened, 105 reports were evaluated for eligibility, and 2 articles with 621 patients were included. The main AK types associated with the development of SCC were found to be baseline AK, also known as a long-standing AK, and merging AK, also called an “AK patch”.

Actinic keratoses (AKs) are common lesions on chronically sun damaged skin, which are morphologically characterized by lower third to full thickness atypia of epidermal keratinocytes. These lesions carry a risk of progression towards invasive squamous cell carcinoma (SCC); therefore, treatment of visible lesions and the field in case of field cancerization is recommended. Treatment of AK includes the destruction of atypical keratinocytes that clinically presents with various degrees of erythema, scaling, crusting, erosion, and other visible and subjective symptoms. Such inflammatory reactions may have an impact on the patient’s social life and have shown to decrease compliance and adherence to therapy. Additionally, as various topical treatments have been proven to be effective in treating AK, tolerability of local site reactions (LSRs) might drive the decision for appropriate treatment in an individual scenario. Therefore, we aimed to review prevalence of severe LSRs among various topical treatments for AK. In addition, we summarized discontinuation rates due to LSRs and possible therapy-unrelated risk factors for the development of LSRs with increased severity.

Hereditary cutaneous melanoma is associated with mutations in the high-risk CDKN2A gene in about 40% of melanoma-prone families. Mutations in the CDK4 gene are the cause in only a few pedigrees. In this study, we analyzed 20 Latvian familial melanoma probands and carried out a comprehensive analysis of CDKN2A including sequencing of its promoter/intronic regions and deletion screening. We also analyzed the critical second exon of the CDK4 gene. One novel intronic variant (IVS2+82C>T) of the CDKN2A gene and a small deletion (c.−20677_−20682delGTACGC) in its promoter region were found. Genotyping of the novel variants in larger melanoma and control groups indicated that the deletion increases the risk of melanoma (odds ratio=6.353, 95% confidence interval: 1.34–30.22, P=0.0168). The CDK4 gene analysis showed a Latvian melanoma family with the mutation R24H carried on the same haplotype as in two previously described Latvian CDK4-positive families. Our study suggests that the main risk gene in Latvian families with a strong family history of melanoma is CDK4 and that most of the other cases analyzed could be sporadic or associated with low-penetrance risk genes.

The aim of this study was to determine whether and how pan-CD44 protein expression in leukoplakia tissues correlates with positive SolCD44 test presence and their role in oral leukoplakia. SolCD44 and total protein expression in saliva were determined using an OncAlert^® Oral Cancer Rapid test. Comparison of paired associations of total protein, SolCD44, mean number of CD44 expressed epithelial layers in leukoplakia tissue, and macrophages below the basement membrane between control group and patients with leukoplakia showed statistically significant results (p < 0.0001). It is shown that the total protein indicates low or elevated risk of possible malignant transformation processes in leukoplakia. Statistically significant differences between higher total protein level and clinical forms of oral leukoplakia (p < 0.0001), as well as CD44-labeled epithelial cell layer decrease (p < 0.0001), were found. This possibly points to the onset of the stemness loss in leukoplakia tissue. CD9 antigen expression in the exosomes of the oral epithelium explained the intercellular flow of SolCD44 and other fluids in the leukoplakia area. We conclude that the OncAlert^® Oral Cancer Rapid test is a valuable screening method in daily clinical practice, in terms of complementing clinical diagnostics methods and to assess the potential for early malignancy.

Background Melanoma incidence and mortality rates are increasing worldwide within the white population. Clinical and histological factors have been usually used for the prognosis and assessment of the risk for melanoma.Objectives The aim of the study was to describe the clinical and histopathological features of the cutaneous melanoma (CM) in the Latvian population, to test the association between melanoma features and patient survival, and to assess the time trends for melanoma incidence.Methods We undertook a descriptive, retrospective analysis of archive data of 984 melanoma patients treated at the largest oncological hospital of Latvia, Riga East University Hospital Latvian Oncology Centre (LOC), between 1998 and 2008. Cox proportional hazards model was used to analyse patient survival and autoregressive models were applied to detect trends in melanoma incidence over time for various categories of melanoma.Results The study showed a significant ascending trend in melanoma incidence in Latvia during the time period from 1998 to 2008 (ß = 1.83, 95% CI = 1.15‐2.91, P = 0.011). Nodular melanoma was the most common tumour subtype with a frequency of 39.2%. Ulceration was present in 45.2% of melanomas. The mean Breslow thickness was 6.0 mm (6.8 mm) and no significant decline in median Breslow thickness was observed during the study period (P = 0.609). A better overall prognosis was detected for females in comparison with males (HR = 1.49; 95% CI = 1.22–1.81; P < 0.001).Conclusions There is a steady increase in melanoma incidence in Latvia with the majority of melanomas diagnosed at late stages with poor prognosis for survival.