WXFL10030390

Facial infiltrating lipomatosis (FIL) is a congenital disorder. The pathogenesis of FIL is associated with PIK3CA mutations, but the underlying mechanisms remain undetermined. We found that the adipose tissue in FIL demonstrated adipocytes hypertrophy and increased lipid accumulation. All adipose-derived mesenchymal stem cells from FIL (FIL-ADSCs) harbored PIK3CA mutations. Moreover, FIL-ADSCs exhibited a greater capacity for adipogenesis. Knockdown of PIK3CA resulted in a reduction in the adipogenic potential of FIL-ADSCs. Furthermore, WX390, a dual-target PI3K/mTOR inhibitor, was found to impede PIK3CA-mediated adipogenesis both in vivo and in vitro. RNA sequencing (RNA-seq) revealed that the expression of transient receptor potential vanilloid subtype 1 (TRPV1) was upregulated after PI3K pathway inhibition, and overexpression or activation of TRPV1 both inhibited adipogenesis. Our study showed that PIK3CA mutations promoted adipogenesis in FIL-ADSCs and this effect was achieved by suppressing TPRV1. Pathogenesis experiments suggested that WX390 may serve as an agent for the treatment of FIL.

Extramammary Paget's disease (EMPD) is a rare intraepithelial adenocarcinoma that occurs in the genitals, axilla, and anus, where apocrine sweat glands are abundant. This disease is mainly characterized by localized lesions and rare distant metastasis. Scrotal Paget's disease is a rare type of EMPD, and there is no standard treatment for metastatic EMPD.

Here, we reported the genetic results of a patient with a PIK3CA gene mutation in scrotal Paget's disease who developed multiple metastases to the lymph nodes, liver, and bones during adjuvant radiotherapy, as well as the results of treatment with a PIK3CA inhibitor. The latest advances in this field were also summarized. The treatment response was evaluated as stable disease (SD) after 6 courses of docetaxel plus tegafur (DS regimen) chemotherapy. Then, a second-line treatment, a PIK3CA inhibitor, WX390, was administered with tolerable toxicity. There was a treatment-induced increase in blood glucose level during treatment, and insulin was administrated with good control. The progression-free survival (PFS) was 3.9 months and the overall survival (OS) was 16 months.

PIK3CA is a commonly mutated gene in EMPD. To the best of our knowledge, this is the first case report of a PIK3CA inhibitor for the treatment of primary metastatic EMPD, and the treatment efficacy was good. PIK3CA inhibitors may be promising for the treatment of metastatic EMPD in the future.