Les tumeurs musculaires lisses de l’utérus

Application of a Patient Derived Xenograft Model for Predicative Study of Uterine Fibroid Disease

Human uterine fibroids, benign tumors derived from the smooth muscle layers of the uterus, impose a major health burden to up to 50% of premenopausal women in their daily life. To improve our understanding of this disease, we developed and characterized a patient-derived xenograft model by subcutaneous transplantation of pieces of human uterine fibroid tissue into three different strains of severe combined immunodeficient mice. Engrafted uterine fibroid tissue preserved the classical morphology with interwoven bundles of smooth muscle cells and an abundant deposition of collagenous matrix, similar to uterine fibroids in situ. The grafts expressed both estrogen receptor 1 and progesterone receptor. Additionally, both receptors were up-regulated by estrogen treatment. Growth of the fibroid grafts was dependent on 17β-estradiol and progesterone supplementation at levels similar to women with the disease and was studied for up to 60 days at maximum. Co-treatment with the antiprogestin mifepristone reduced graft growth (four independent donors, p<0.0001 two-sided t-test), as did treatment with the mTOR inhibitor rapamycin (three independent donors, p<0.0001 two-sided t-test). This in vivo animal model preserves the main histological and functional characteristics of human uterine fibroids, is amenable to intervention by pharmacological treatment, and can thus serve as an adequate model for the development of novel therapies.

[Uterine leiomyosarcoma: epidemiology, pathology, biology, diagnosis, prognosis and treatment]

Uterine leiomyosarcoma is a rare disease with a poor prognosis. The rarity of this tumor needs a specialized management in tertiary reference centers in order to provide patients with optimal diagnostic, prognostic and therapeutic care. The pathological diagnosis relies on the presence of three characteristics in proliferating smooth muscle cells: necrosis, cytologic atypia and mitosis. Despite progress in the knowledge of the biology of these tumors, no oncogenic driver has been found. Prognosis depends mainly on the age of the patient, race, FIGO stage, mitotic index and hormonal receptor expression in the tumor. Surgery is one of the cornerstones of management and cytotoxic chemotherapy is the mainstay of treatment in metastatic disease with a potential role in the adjuvant setting. In locally advanced or metastatic disease, prognosis is poor with a median overall survival of about 12 to 14 months despite a 30% response rate to polychemotherapy regimens. Anti-angiogenics and hormonal therapy have a role to play in the setting of metastatic disease. It is mandatory to include such patients in clinical trials aiming to improve the therapeutic management of these patients. Multimodal therapy can improve the prognosis of selected patients too.

Diagnostic value of progesterone receptor and p53 expression in uterine smooth muscle tumors

Background

The diagnosis of uterine smooth muscle tumors depends on a combination of microscopic features. However, a small number of these tumors still pose difficult diagnostic challenges.

Aim

To investigate progesterone receptor (PR) and p53 expression in leiomyomas (LMs), atypical leiomyomas (ALMs), smooth muscle tumors of uncertain malignant potential (STUMP), and leiomyosarcomas (LMSs) and to evaluate the potential utility of the selected immunohistochemical markers in differentiating these tumors.

Materials and methods

Immunohistochemical expression of PR and p53 was investigated in 41 uterine smooth muscle tumors comprising: 15 LMS, 4 STUMP, 6 ALM and 16 LM. Quantitative evaluation of PR and p53 expression was graded on a scale from 0 to 3+.

Results

Leiomyosarcomas showed reduced PR expression. All LMs as well as ALMs and STUMP were stained intensely for PR. Conversely, LMS was strongly stained with p53, while the three non-sarcomatous groups (STUMP, ALM, LM) were either entirely negative or weakly stained for p53. Regarding both PR and p53 expression, the difference between the LMS group and the three non-sarcomatous groups was highly significant (p < 0.001). Combined high PR - low p53 expression was seen in all the 26 examined cases of the non-sarcomatous group including the STUMP cases and none of the LMS cases. Therefore, it represents a "benign" profile with 100% specificity in diagnosis of a non-sarcomatous tumor.

Conclusion

Immunohistochemistry for PR and p53 is valuable as an adjunct tool to morphological assessment of problematic uterine smooth muscle tumors.