The Hunt for Baby Melanomas: A Prospective Study of the Dermoscopy Features on 100 Small Melanoma Cases with in Vivo Surface Diameters up to a Maximum of 6 mm.

Introduction: Early diagnosis can improve melanoma prognosis. Dermoscopy can enhance early melanoma recognition. Objectives: Examine the dermoscopy features of early melanoma up to a maximum surface diameter of 6 mm. Methods: Consecutive melanoma cases were collected from two medical practices in Sydney, Australia 2019-2021. Dermoscopy features were recorded for melanomas by maximum surface diameter, to the nearest 0.1 mm, to a limit of 6 mm. Results: Total cases numbered 100; with males (N = 48) and females (N = 52), melanoma in situ (MIS, N = 96) and invasive (N = 4). The most frequent anatomic sites on both males and females were back (males N = 20, females N = 16) then knee or leg (males N = 8, females N = 12). Minimum respective MIS diameters for males/females was 1.2/2.0 mm and for invasive cases 2.0/3.4 mm. Highest frequency dermoscopy features were: light brown, dark brown, gray and asymmetric melanoma shape. Brown pigment in hair follicles were more frequent on legs compared to other anatomic sites (odds ratio [OR] 14.6; 95% CI 1.29-165.17, P 0.03). Pseudopods were substantially increased in frequency comparing diameters less than 4 mm with 4 up to 6 mm (OR 8.81; 95% CI 1.05-73.9, P 0.004). Structureless area cases recorded increased gray (OR 7.08; 95% CI 1.61-31.11, P=0.01). Melanomas with edge angulation were noted in 20%-50% of cases across diameters 1-6 mm, less frequent were pigmented circles and polygons. Conclusions: Watch out! MIS presented with a surface diameter of just 1.2 mm and invasive melanoma 2.5 mm. Pseudopods were a strong clue to melanomas with a surface diameter less than 5mm. We found melanomas on leg sites displayed more frequent pigmented hair follicles.

Dual ablation of Grb10 and Grb14 in mice reveals their combined role in regulation of insulin signaling and glucose homeostasis.

Growth factor receptor bound (Grb)10 and Grb14 are closely related adaptor proteins that bind directly to the insulin receptor (IR) and regulate insulin-induced IR tyrosine phosphorylation and signaling to IRS-1 and Akt. Grb10- and Grb14-deficient mice both exhibit improved whole-body glucose homeostasis as a consequence of enhanced insulin signaling and, in the case of the former, altered body composition. However, the combined physiological role of these adaptors has remained undefined. In this study we utilize compound gene knockout mice to demonstrate that although deficiency in one adaptor can enhance insulin-induced IRS-1 phosphorylation and Akt activation, insulin signaling is not increased further upon dual ablation of Grb10 and Grb14. Context-dependent limiting mechanisms appear to include IR hypophosphorylation and decreased IRS-1 expression. In addition, the compound knockouts exhibit an increase in lean mass comparable to Grb10-deficient mice, indicating that this reflects a regulatory function specific to Grb10. However, despite the absence of additive effects on insulin signaling and body composition, the double-knockout mice are protected from the impaired glucose tolerance that results from high-fat feeding, whereas protection is not observed with animals deficient for individual adaptors. These results indicate that, in addition to their described effects on IRS-1/Akt, Grb10 and Grb14 may regulate whole-body glucose homeostasis by additional mechanisms and highlight these adaptors as potential therapeutic targets for amelioration of the insulin resistance associated with type 2 diabetes.