SK-MEL-5 is a human melanoma cell line that has been used in various studies to explore new therapies against melanoma in different in vitro experiments. Based on this study we report on the development of quantitative structure-activity relationship (QSAR) models able to predict the cytotoxic effect of diverse chemical compounds on this cancer cell line. The dataset of cytotoxic and inactive compounds were downloaded from the PubChem database. It contains the data for all chemical compounds for which cytotoxicity results expressed by GI 50 was recorded. In total 13 blocks of molecular descriptors were computed and used, after appropriate pre-processing in building QSAR models with four machine learning classifiers: Random forest (RF), gradient boosting, support vector machine and random k-nearest neighbors. Among the 186 models reported none had a positive predictive value (PPV) higher than 0.90 in both nested cross-validation and on an external dataset testing, but 7 models had a PPV higher than 0.85 in both evaluations, all seven using the RFs algorithm as a classifier, and topological descriptors, information indices, 2D-autocorrelation descriptors, P-VSA-like descriptors, and edge-adjacency descriptors as sets of features used for classification. The y-scrambling test was associated with considerably worse performance (confirming the non-random character of the models) and the applicability domain was assessed through three different methods.

Graham-Little-Piccardi-Lasseur syndrome (GLPLS) is a rare lichenoid dermatosis characterized by progressive cicatricial alopecia of the scalp, the loss of pubic and axillary hair, and keratosis pilaris. The syndrome is considered a form of follicular lichen planus. 1 Clinically, GLPLS is characterized by a triad of features that include scarring alopecia of the scalp, non-cicatricial alopecia of the axillae and pubis, and a lichenoid follicular eruption. It was initially described by Piccardi in 1913 and in 1915, Graham-Little published a similar case observed by Lassueur. 2 Case reportA 38-year-old man presented with a pruritic eruption that involved the trunk and upper extremities and had appeared over the previous three weeks. At the consultation, follicular, dark red, spiny, hard, and adherent papules measuring 1-3 mm in diameter were observed. Some of these papules were massed in groups located on the inside of both arms and on the patient's back (Fig. 1a, b). Linear excoriations and some pustules, probably arising in response to a secondary infection caused by itching, were also observed. Over the past five years, the patient had noted patchy hair loss that developed and progressed slowly, without any local or general symptoms. On examination, patches of non-scarring alopecia were observed in the right axilla and the suprapubic area (Fig. 1c, d). This axillary and pubic hair loss had developed over the previous two years.Patches of scarring alopecia without erythema were apparent on the scalp (Fig. 2). The patchy hair loss on the scalp had been diagnosed as alopecia areata, and the patient had been treated with local steroids and vasodilators without effect. He had not been treated for the hair loss in the axillary and pubic areas. However, in the year immediately prior to presentation, the patient had not taken any medication for the disease. He was not concerned about the disease but was distressed about the severe pruritus caused by the most recent cutaneous eruption. The patient denied any constitutional symptoms. His medical history was unremarkable. A general clinical examination of systems and organs found nothing relevant. No specific laboratory data were found. A biopsy of one of the new eruptive lesions revealed a follicular lichen planus. Histopathology described a dense perifollicular lymphocytic infiltrate, extending into the basal layer, with a focal vacuolar alteration of the follicular basement membrane (Fig. 3). Based on the clinical presentation of cicatricial alopecia on the scalp and non-cicatricial alopecia in the axillary and pubic areas, and the histopathologic confirmation of follicular lichen planus, GLPLS was diagnosed. DiscussionGraham-Little-Piccardi-Lasseur syndrome is a rare lichenoid dermatosis. Most patients present with clinical findings commonly considered to represent the triad of findings in GLPLS in the following order: multifocal cica-1019 ª

No abstract