Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients’ values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.

Objective: Dysphagia is a common clinical condition characterized by difficulty in swallowing. It is sub-classified into oropharyngeal dysphagia, which refers to problems in the mouth and pharynx, and esophageal dysphagia, which refers to problems in the esophageal body and esophagogastric junction. Dysphagia can have a significant negative impact one’s physical health and quality of life as its severity increases. Therefore, proper assessment and management of dysphagia are critical for improving swallowing function and preventing complications. Thus a guideline was developed to provide evidence-based recommendations for assessment and management in patients with dysphagia. Methods: Nineteen key questions on dysphagia were developed. These questions dealt with various aspects of problems related to dysphagia, including assessment, management, and complications. A literature search for relevant articles was conducted using Pubmed, Embase, the Cochrane Library, and one domestic database of KoreaMed, until April 2021. The level of evidence and recommendation grade were established according to the Grading of Recommendation Assessment, Development and Evaluation methodology. Results: Early screening and assessment of videofluoroscopic swallowing were recommended for assessing the presence of dysphagia. Therapeutic methods, such as tongue and pharyngeal muscle strengthening exercises and neuromuscular electrical stimulation with swallowing therapy, were effective in improving swallowing function and quality of life in patients with dysphagia. Nutritional intervention and an oral care program were also recommended. Conclusion This guideline presents recommendations for the assessment and management of patients with oropharyngeal dysphagia, including rehabilitative strategies.

Traditionally, pathologists microscopically examine tissue sections to detect pathological lesions; the many slides that must be evaluated impose severe work burdens. Also, diagnostic accuracy varies by pathologist training and experience; better diagnostic tools are required. Given the rapid development of computer vision, automated deep learning is now used to classify microscopic images, including medical images. Here, we used a Inception-v3 deep learning model to detect mouse lung metastatic tumors via whole slide imaging (WSI); we cropped the images to 151 by 151 pixels. The images were divided into training (53.8%) and test (46.2%) sets (21,017 and 18,016 images, respectively). When images from lung tissue containing tumor tissues were evaluated, the model accuracy was 98.76%. When images from normal lung tissue were evaluated, the model accuracy (“no tumor”) was 99.87%. Thus, the deep learning model distinguished metastatic lesions from normal lung tissue. Our approach will allow the rapid and accurate analysis of various tissues.

Background: Skin aging can be divided into intrinsic and extrinsic processes, and occur due to several factors. Although the interest in skin youthfulness is increasing globally, research on facial skin youthfulness and lifestyle is limited. Objective: This study aimed to evaluate the association between facial skin youthfulness and biophysical facial skin parameters in Korean women over 50 years of age. We further investigated lifestyle factors that make people appear younger than their chronological age. Methods: We surveyed the essential information and lifestyle of subjects by questionnaires, and measured the biophysical parameters of the facial skin. We then performed clinical facial assessments, and the values were compared with the chronologic age. The associations between age differences, biophysical parameters, and living habits were evaluated. Results: We identified a positive correlation between age and melanin index (r=0.245, p＜0.001) and erythema index (r=0.119, p=0.002). The melanin index was statistically significantly lower in the group without regular outdoor activities (144.66±43.24 vs. 137.00±55.48, p=0.043). The melanin index and erythema index were the significant differences that defined younger perceived age than chronological age. The perceived age was younger in the group who wore a hat when performing outdoor activities than the group who did not (3.70±1.84 vs. 3.40±1.94, p=0.034). Conclusion To retain youthful skin, it is essential to reduce sun exposure, as this factor can affect the melanin and erythema indices by inducing photoaging. Therefore, avoiding the sun bia proper methods, such as wearing a hat and sunscreen during outdoor activities, is recommended to maintain skin youthfulness.

Background: Acral melanoma is the most common subtype of melanoma among Koreans, and regional or distant metastasis is an indicator of poor prognosis. Yes-associated protein (YAP), a key effector of the Hippo pathway, is known to induce tumor progression and metastasis in various cancers. Objective: We aimed to analyze the clinical and histopathological characteristics of acral melanoma among Koreans and to evaluate their association with YAP expression. Methods: This retrospective review included 27 patients with acral melanoma. Clinical features including age, sex, lesion site, and stage were obtained from the medical records and images. Biopsy slides of patients with acral melanoma were reviewed, and immunohistochemical staining for YAP was performed. Results: The rate of YAP expression was significantly higher in patients having acral melanoma with regional or distant lymph node (LN) metastasis than in those without metastasis (n=4/5, 80.0% vs. n=2/22, 9.1%; p=0.004). Histopathologically, the rate of YAP expression was higher in patients having acral melanoma with lymphovascular invasion than in those without lymphovascular invasion (n=4/8, 50.0% vs. n=2/19, 10.5%; p=0.044). Among the 27 lesions, 14 (51.9%) were on stress-bearing sites such as the forefoot and heel. However, the rate of YAP expression did not differ significantly between weight-bearing and non-weight-bearing locations (p=0.834). Conclusion YAP expression is significantly associated with metastasis, especially LN metastasis, in patients with acral melanoma. Therefore, YAP expression may be used as a prognostic factor for LN metastasis and a target for novel treatments in patients with melanoma.

Background: Pathogenesis of psoriasis is related to dysregulated keratinocyte function and immune responses. Genetic background is one of the most important factors in disease pathogenesis. However, psoriasis-associated genes have not yet been fully identified. Activating transcription factor 3 (ATF3) is a member of the cyclic adenosine monophosphate responsive element-binding protein family of transcription factors, which may regulate epidermal keratinocytes. Objective: We aimed to evaluate the effects of ATF3 on inflammation and differentiation of keratinocytes. Methods: We evaluated the expression of ATF3 in polyinosinic:polycytidylic acid (poly[I:C])-treated keratinocytes. Subsequently, we compared ATF3 levels in psoriatic and normal skin using immunohistochemical staining. To illustrate the role of ATF3, we generated ATF3-overexpressing keratinocytes and ATF3-knockdown keratinocytes using a recombinant adenovirus. We investigated inflammation and differentiation of keratinocytes by measuring the mRNA levels of inflammatory cytokines and differentiation markers. Results: Treatment of keratinocytes with poly(I:C) increased ATF3 expression in a time-dependent manner. Immunohistochemical staining showed that ATF3 expression was increased in the epidermis of psoriatic tissues. When ATF3 was overexpressed in keratinocytes using a recombinant adenovirus, poly(I:C)-induced inflammation was reduced. Conversely, ATF3 knockdown increased poly(I:C)-induced inflammation. Thus, ATF3 overexpression inhibited keratinocyte differentiation, while ATF3 knockdown promoted it. Conclusion ATF3 may be involved in the pathogenesis of psoriasis by influencing the inflammatory response and differentiation of keratinocytes.

Background: Reduced lipid content in the stratum corneum is a major cause of skin-barrier dysfunction in various pathological conditions. Promoting lipid production is a potential strategy to improve skin-barrier function. Recent evidence supports the beneficial effects of adiponectin on lipid metabolism and senescence in keratinocytes. Objective: This study aimed to investigate whether plant extracts can enhance skin-barrier function. Methods: We screened fruit and herb extracts that enhance the lipid synthesis of keratinocytes via AMP-activated protein kinase (AMPK) activation and SIRT1 signaling in the adiponectin pathway. The levels of major lipid synthesis enzymes and transcription factors as well as epidermal barrier lipids involved in adiponectin-associated epidermal barrier formation were evaluated in the herbal extracts- or adiponectin-treated human epidermal keratinocyte and equivalent models. The mRNA expression of major lipid synthesis enzymes increased following treatment with Lycii Fructus, Prunus tomentosa, and Melia toosendan extracts. Results: The expression of transcription factors SIRT1, liver X receptor α, peroxisome proliferator-activated receptors (PPARs), and sterol regulatory element-binding proteins (SREBPs) were upregulated. Levels of free fatty acids, cholesterol, and ceramides were elevated. The expression of keratinocyte differentiation markers increased. In particular, among fruit extracts with a detectable effect, Melia toosendan induced the highest expression of lipid synthase. Conclusion These results indicate that Melia toosendan is a promising candidate for improving skin-barrier function.

Background: Alopecia areata (AA) is an autoimmune disease characterized by chronic inflammation, the pathogenesis of which is unknown. Stress is believed to play a role; however, evidence remains insufficient. A recent study showed that substance P (SP) damaged hair follicles by causing neurogenic inflammation, activating perifollicular mast cells, and inducing keratinocyte apoptosis. Objective: We aimed at studying the role of SP in AA pathogenesis. We investigated the SP levels in the lesional scalp tissues and serum. We also studied the effect of SP on the inflammatory response and hair growth in the outer root sheath (ORS) cells. Methods: We compared the serum levels of SP in 58 AA patients and 28 healthy subjects.Then, we checked the expression of SP and SP receptor, neurokinin-1 receptor (NK-1R) in the scalps of AA patients and healthy controls using immunohistochemical staining.Finally, we analyzed the mRNA expression of inflammatory cytokines and hair growthrelated factors in ORS cells. Results: SP and NK-1R expression were markedly higher in the hair follicles and interfollicular epidermis of the scalp lesions of AA patients. However, there was no statistically significant difference in serum SP levels between controls and patients, regardless of the type of alopecia. SP significantly increased the mRNA expression of inflammatory cytokines and decreased hair growth-related growth factors in ORS cells, but the results were not dramatic. Conclusion SP triggered a localized micro-inflammation in lesional hair follicles, provoked an inf lammatory response, and inhibited hair growth, thereby confirming the pathogenic role of SP in AA.

Background: Psoriasis is a chronic inflammatory skin disease. The etiology of psoriasis is not fully understood, but the genetic background is considered to be the most important factor. To date, many psoriasis-related genes have been discovered, but the role of many important genes has not been well understood. Objective: The purpose of this study is to uncover possible roles of MDA5 in psoriasis. Methods: Expression of MDA5 was investigated using immunohistochemistry. Then, MDA5 was overexpressed in keratinocytes using a recombinant adenovirus. Results: As a result of immunohistochemical staining, the expression of MDA5 was significantly increased in the epidermis of psoriasis compared to normal skin. Similarly, the expression of MDA5 was increased in imiquimod-induced psoriasiform dermatitis model. In cultured keratinocytes, toll-like receptor 3 agonist poly(I:C) induced expression of MDA5 at both mRNA and protein levels. When MDA5 was overexpressed using a recombinant adenovirus, poly(I:C)-induced cytokine expression was significantly increased. Finally, MDA5 overexpression significantly inhibited calcium-induced differentiation of keratinocytes. Conclusion These results suggest that MDA5 increases in psoriasis and negatively regulates keratinocyte differentiation.

Background: Increased sebum secretion is considered the main causative factor in the pathogenesis of acne. There is an unmet pharmacological need for a novel drug that can control sebum production with a favorable adverse effect profile. Objective: To investigate the effect of azidothymidine on lipid synthesis in sebocytes and to identify the underlying mechanism of the inhibitory effect of azidothymidine on insulin-like growth factor (IGF)-1-induced lipid synthesis in sebocytes. Methods: Immortalized human sebocytes were used for the analysis. Thin-layer chromatography (TLC) and Oil Red O staining were performed to evaluate lipid synthesis in the sebocytes. The differentiation, lipid synthesis, mitochondrial biogenesis, and mitophagy in sebocytes were investigated. Results: TLC and Oil Red O staining revealed that azidothymidine reduced IGF-1 induced lipid synthesis in the immortalized human sebocytes. Azidothymidine also reduced IGF-1-induced expression of transcriptional factors and enzymes involved in sebocyte differentiation and lipid synthesis, respectively. Moreover, we found that IGF-1 upregulated the levels of peroxisome proliferator-activated receptor-gamma coactivator-1α, LC-3B, p62, and Parkin, major regulators of mitochondrial biogenesis and mitophagy in immortalized human sebocytes. In contrast, azidothymidine inhibited IGF-1 induced mitochondrial biogenesis and mitophagy in the sebocytes. Conclusion These results suggest that azidothymidine downregulates IGF-1-induced lipogenesis by dysregulating the quality of mitochondria through suppression of mitochondrial biogenesis and mitophagy in immortalized human sebocytes. Our study provides early evidence that azidothymidine may be an effective candidate for a new pharmacological agent for controlling lipogenesis in sebocytes.