Perianal basosquamous carcinoma treated with radiation therapy, a case report.

Background: Perianal basal cell carcinoma (BCC) is very rare and estimated to account for 0.08% of all BCC and 0.02% of all anorectal neoplasms. Perianal lesions are more likely to be squamous cell carcinoma (SCC) as BCC usually develops on areas of skin exposed to ultraviolet (UV) light such as the face and arms. Proper diagnosis with the assistance of immunohistochemistry (IHC) stains to distinguish the two entities can help inform the suitable course of treatment. Case Description: Our case is an 82-year-old male with a history of cutaneous BCC on the arms and trunk presenting with a symptomatic perianal lesion. Initial biopsy demonstrated BCC with subsequent IHC studies differentiating from basaloid SCC. Standard treatment includes wide local excision (WLE) but given his poor performance status, radiation only was recommended. He was successfully treated and tolerated 30 Gy in 5 daily fractions. Conclusions: Radiation only is a unique and feasible non-surgical treatment for basosquamous carcinoma of the anus.

V600E BRAF mutation in pilocytic astrocytoma is associated with a more diffuse growth pattern but does not confer a more aggressive clinical behavior.

Activation in mitogen activated protein kinase signaling pathway has recently been described as a predominant event in pilocytic astrocytoma (PA) and is commonly caused by constitutively active mutation in BRAF protein. Whereas PA of posterior fossa in children have a high prevalence of BRAF duplication and fusion, primary molecularm abnormalities in supratentorial tumors of adults are more diverse and also include BRAF V600E point mutation. In our study we evaluated 51 PAs for BRAF duplication and BRAF V600E point mutation. We found a relatively high frequency of V600E mutation in our cohort. Histologically, V600E-carrying PA appeared more infiltrative, yet our limited clinical follow-up failed to detect a deleterious prognostic significance.

Interactions between GIPC-APPL and GIPC-TRP1 regulate melanosomal protein trafficking and melanogenesis in human melanocytes.

By virtue of the presence of multiple protein-protein interaction and signaling domains, PDZ proteins play important roles in assembling protein complexes that participate in diverse cell biological processes. GIPC is a versatile PDZ protein that binds a variety of target proteins in different cell types. In previous studies we showed that, in epidermal melanocytes, GIPC interacts with newly synthesized melanosomal protein TRP1 in the Golgi region and proposed that this interaction may facilitate intracellular trafficking of TRP1. However, since GIPC contains a single PDZ domain and no other known protein interaction motifs, it is not known how GIPC-TRP1 interaction affects melanosome biogenesis and/or melanin pigmentation. Here, we show that in human primary melanocytes GIPC interacts with AKT-binding protein APPL (adaptor protein containing pleckstrin homology, leucine zipper and phosphotyrosine binding domains), which readily co-precipitates with newly synthesized TRP1. Knockdown of either GIPC or APPL inhibits melanogenesis by decreasing tyrosinase protein levels and enzyme activity. In melanocytes, APPL exists in a complex with GIPC and phospho-AKT. Inhibition of AKT phosphorylation using a PI3-kinase inhibitor abolishes this interaction and results in retardation TRP1 in the Golgi. These data suggest that interactions between TRP1-GIPC and GIPC-APPL-AKT provide a potential link between melanogenesis and PI3 kinase signaling.