Expression of Programmed Death-Ligand 1 and Programmed Death-1 in Patients with Extramammary Paget's Disease

FOXM1: a new therapeutic target of extramammary Paget disease

Extramammary Paget disease (EMPD) is a rare skin cancer that primarily affects older individuals predominantly in areas with apocrine sweat glands. Although most early EMPD lesions are indolent, patients with metastatic EMPD have a poor prognosis due to the lack of effective systemic treatment. In this study, we investigated the role of forkhead box M1 (FOXM1), a potent transcription factor, in EMPD and assessed the potential of FOXM1 as a therapeutic target. Immunohistochemistry of 112 primary and 17 metastatic EMPD samples revealed that FOXM1 expression increased with tumor progression. Patients in whom FOXM1 was expressed in more than 10% of tumor cells had significantly shorter disease-specific survival than the other patients (p = 0.0397). In in vitro studies using our newly established EMPD cell line, KS-EMPD-1, we found high expression of FOXM1. Knockdown of FOXM1 impaired tumor cell viability, migration, and invasion. Inhibition of FOXM1 using thiostrepton also reduced tumor cell viability in a dose-dependent manner. These findings suggest that FOXM1 is a promising therapeutic target for patients with EMPD.

KS-EMPD-1: a novel cell line of primary extramammary Paget's disease

Extramammary Paget's disease (EMPD) is a rare skin cancer that mainly occurs in apocrine sweat gland-rich areas in elderly people. The prognosis of metastatic EMPD is unfavorable because of the lack of fully effective systemic therapies. However, the difficulty in establishing a model of EMPD has hampered basic research for exploring its pathogenesis and optimal treatments. Here, we established for the first time an EMPD cell line (named KS-EMPD-1) from a primary tumor on the left inguinal region of an 86-year-old Japanese male. The cells were successfully maintained for more than 1 year, with a doubling time of 31.2 ± 0.471 h. KS-EMPD-1 exhibited constant growth, spheroid formation, and invasiveness, and was confirmed to be identical to the original tumor by short tandem repeat analyses, whole exome sequencing, and immunohistochemistry (CK7+CK20-GCDFP15+). Western blotting of the cells revealed the protein expression of HER2, NECTIN4, and TROP2, which have recently attracted attention as potential therapeutic targets for EMPD. KS-EMPD-1 was highly sensitive to docetaxel and paclitaxel on chemosensitivity test. The KS-EMPD-1 cell line is a promising resource for basic and preclinical research on EMPD to better define the tumor characteristics and treatment strategy of this rare cancer.

Extramammary Paget's Disease of genitourinary origin

PURPOSE OF REVIEW

Extramammary Paget's Disease (EMPD) is an uncommon intra-epithelial malignancy, affecting primarily apocrine gland-bearing skin. EMPD is often considered an orphan diagnosis given its rarity. This review provides a contemporary overview of EMPD management.

RECENT FINDINGS

The mainstay of EMPD treatment centers around a high index of suspicion to allow for an early and accurate diagnosis, wide local or Mohs micrographic surgical excision with care paid toward the margin status, and thoughtful consideration for lymphadenectomy in patients with clinically positive regional disease. There is currently no consensus regarding adjuvant therapies or systemic therapies although with ongoing improvements in tumor biology and genomics, including molecular pathways and alterations specific to EMPD, targeted or combinatorial therapies may be on the horizon.

SUMMARY

Clinicians caring for patients with EMPD should seek consultation from or if feasible, consider referral to high-volume, experienced centers with patients counseled and provided with frequent and close follow-up for disease recurrence or progression. Collaboration with groups such as the Global Society for Rare Genitourinary Tumors, and especially patient groups will be vital to designing trials and collaborative databases.