Alterations of the MEK/ERK, BMP, and Wnt/ß-catenin pathways detected in the blood of individuals with lymphatic malformations.

Lymphatic malformation (LM) is a developmental anomaly of the lymphatic system that may lead to disfigurement, organ dysfunction and recurrent infection. Though several treatment modalities exist, pharmacotherapy is often associated with side effects and recurrence is common following surgical interventions. Moreover, despite the recent discovery of PIK3CA mutations in lymphatic endothelial cells of LM patients, the full spectrum of molecular pathways involved in LM pathogenesis is poorly understood. Here, we performed RNA sequencing on blood samples obtained from ten LM patients and nine healthy subjects and found 421 differentially expressed genes that stratify LM subjects from healthy controls. Using this LM gene signature, we identified novel pathway alterations in LM, such as oxidative phosphorylation, MEK/ERK, bone morphogenetic protein (BMP), and Wnt/ß-catenin pathways, in addition to confirming the known alterations in cell cycle and the PI3K/AKT pathway. Furthermore, we performed computational drug repositioning analysis to predict existing therapies (e.g. sirolimus) and novel classes of drugs for LM. These findings deepen our understanding of LM pathogenesis and may facilitate non-invasive diagnosis, pathway analysis and therapeutic development.

Lymphocytopenia in children with lymphatic malformation.

OBJECTIVE: To determine whether an immunologic abnormality exists in patients with lymphatic malformation (LM). DESIGN: Retrospective case series. SETTING: Tertiary care pediatric hospital. PATIENTS: Twenty-one consecutive patients (11 male and 10 female) undergoing LM treatment. INTERVENTIONS: Clinical data (ie, age, clinical LM stage, radiographic appearance, and histologic findings) were correlated with complete blood cell count and detailed lymphocyte differential. Complete blood cell counts and lymphocyte subsets were measured in 21 and 18 patients, respectively. RESULTS: The average age at the time of testing was 67 months (range, 1-231 months). The patients were categorized according to LM stage, including 4 (19%) with stage 1, 4 (19%) with stage 2, 4 (19%) with stage 3, 7 (33%) with stage 4, and 2 (10%) with stage 5 disease. Radiographic LM appearance was macrocystic in 6 patients (29%), mixed macrocystic and microcystic in 8 (38%), and microcystic in 7 (33%). Complete blood cell count data demonstrated lymphocytopenia in 6 patients (29%). The results of the lymphocyte subset tests showed concomitant T-, B-, and natural killer (NK)-cell deficiency in 6 (33%) of 18 patients. All 6 patients with T-cell lymphocytopenia had normal neutrophil and platelet counts. Spearman rank and chi(2) analyses showed that LM stage 4 or 5 and microcystic LM were significantly associated with lymphocytopenia (P = .002 and P = .008, respectively). Histologic analysis did not demonstrate increased lymphocytes in any LM specimens. CONCLUSION: We found T, B, and NK lymphocytopenia in patients with large bilateral or microcystic LM. Although the relationship between lymphocytopenia and infection was not addressed in this study, the recognition of lymphocytopenia in patients with LM may have important clinical and prognostic implications.

Renal lymphangiectasia associated with chronic myeloid leukemia.

Renal lymphangiectasia is a rare disorder characterized by dilatation of peripelvic, renal and perirenal lymphatic ducts. The exact etiology is not known. Congenital forms and ac-quired forms have been described. The latter has been attributed to obstruction of draining retro-peritoneal lymphatic ducts caused by either infection, inflammation or any other cause. We des-cribe the rare association of renal lymphangiectasia with chronic myeloid leukemia, which is probably not yet reported in the medical literature.