Inhibition of aberrantly overexpressed Polo-like kinase 4 is a potential effective treatment for DNA damage repair-deficient uterine leiomyosarcoma.

PURPOSE: Uterine leiomyosarcoma (LMS) is an aggressive sarcoma and a subset of which exhibit DNA repair defects. Polo-like kinase 4 (PLK4) precisely modulates mitosis, and its inhibition causes chromosome missegregation and increased DNA damage. We hypothesize that PLK4 inhibition is an effective LMS treatment. EXPERIMENTAL DESIGN: Genomic profiling of clinical uterine LMS samples was performed, and homologous recombination (HR) deficiency scores were calculated. PLK4 inhibitor (CFI-400945) with and without an ataxia telangiectasia mutated (ATM) inhibitor (AZD0156) were tested in vitro on gynecological sarcoma cell lines SK-UT-1, and SKN, and SK-LMS-1. Findings were validated in vivo using the SK-UT-1 xenograft model in Balb/c nude mouse model. The effects of CFI-400945 were also evaluated in a BRCA2 knockout SK-UT-1 cell line. The mechanisms of DNA repair were analyzed using a DNA damage reporter assay. RESULTS: Uterine LMS had a high HR deficiency score, overexpressed PLK4 mRNA, and displayed mutations in genes responsible for DNA repair. CFI-400945 demonstrated effective antitumor activity in vitro and in vivo. The addition of AZD0156 resulted in drug synergism, largely due to a preference for nonhomologous end-joining (NHEJ) DNA repair. Compared to wild-type cells, BRCA2 knockouts were more sensitive to PLK4 inhibition when both HR and NHEJ repairs were impaired. CONCLUSIONS: Uterine LMS with DNA repair defects is sensitive to PLK4 inhibition because of the effects of chromosome missegregation and increased DNA damage. Loss-of-function BRCA2 alterations or pharmacological inhibition of ATM enhanced the efficacy of PLK4 inhibitor. Genomic profiling of an advanced-stage or recurrent uterine LMS may guide therapy.

Predictive biomarkers and tumor microenvironment in female genital melanomas: a multi-institutional study of 55 cases.

Female genital melanomas are rare. At diagnosis, most affected patients have advanced disease. Surgery remains the primary treatment, and adjuvant therapy is largely ineffective. Recently, immune checkpoints and the mitogen-activated protein kinase pathway have been explored as treatment targets. However, evaluation of these biomarkers in genital melanomas is limited. We evaluated the clinicopathological features of 20 vulvar, 32 vaginal, and three cervical melanomas and assessed programmed cell death ligand 1 (PD-L1) expression, CD8 tumor-infiltrating lymphocyte density, mismatch repair proteins, VE1 immunohistochemistry, and KIT and BRAF mutations. The median age of the patients was 66 years, and median tumor sizes were 25, 30, and 20 mm for vulvar, vaginal, and cervical tumors, respectively. Mean mitotic figures were 18, 19, and 30 per mm2. Thirty-seven patients (67%) had operable tumors. After a median follow-up of 15 months, only nine patients (16%) were alive. Eight of the nine survivors did not have lymph node metastasis. Using 5% as the threshold, PD-L1 expression was observed in 55%, 50%, and 33% of vulvar, vaginal, and cervical tumors, respectively, when the Roche SP263 antibody was used and 20%, 53%, and 0%, respectively, when the Dako 28-8 antibody was used. The median CD8 tumor-infiltrating lymphocyte density was significantly higher in vulvar/vaginal than cervical melanomas and correlated with PD-L1 expression. No cases exhibited loss of mismatch repair proteins. Five cases harbored KIT mutations, three of which were hotspots. BRAF V600E mutation was not detected. Univariable analysis showed that tumor size greater than or equal to 33 mm, mitotic figures of greater than or equal to 10 per mm2, lymph node metastasis, and low CD8+ tumor-infiltrating lymphocyte density were adverse prognostic factors. Thus, patients with genital melanomas have a poor prognosis, and evaluation of multiple biomarkers is necessary to identify patients who may benefit from immunotherapy or targeted therapy.

Napsin A, Hepatocyte Nuclear Factor-1-Beta (HNF-1ß), Estrogen and Progesterone Receptors Expression in Arias-Stella Reaction.

BACKGROUND: The Arias-Stella reaction (ASR) can mimic endometrial clear cell carcinoma (ECCC) in small biopsies, especially when drug or pregnancy history is unknown. A panel of immunohistochemical markers comprising napsin A, hepatocyte nuclear factor-1-beta (HNF-1ß), estrogen and progesterone receptors (ER, PR) has been found useful in confirming a diagnosis of ECCC. However, the detailed characterization of how expression of this combination of markers in the ECCC mimics ASR has yet to be thoroughly evaluated. DESIGN: The frequency and extent of napsin A, HNF-1ß, ER, and PR expression in ASR were assessed in a large series. For napsin A, any cytoplasmic staining was considered positive while only nuclear staining was deemed to be positive for HNF-1ß, ER, and PR. Immunohistochemical histoscores based on the intensity and extent of staining were calculated. RESULTS: Forty cases were gestational and 10 were nongestational ASR. In 19 (38%), the reaction was extensive and involved >50% of the glands. A stromal decidual change was found in 31 (77.5%) of the gestational and 3 (30%) of the nongestational cases. Napsin A was positive in all gestational and 8 of 10 (80%) nongestational ASR. All ASR showed HNF-1ß expression. ER expression was reduced in 37 (92.5%) and lost in 3 (7.5%) gestational ASR, and reduced in 9 (90%) and lost in 1 (10%) of nongestational ASR. None of the ASR in our series expressed PR. CONCLUSIONS: Naspin A and HNF-1ß were frequently expressed in both gestational and nongestational ASR, and ER expression was usually either reduced or loss. Interpretation of these markers in small biopsies containing atypical clear cells should be made with caution.

The mitosis-specific marker phosphohistone-H3 (PHH3) is an independent prognosticator in uterine smooth muscle tumours: an outcome-based study.

AIMS: Accurate mitosis counting, which is important in the diagnosis of uterine smooth muscle tumours (USMTs), is often difficult and subjective. The mitosis-specific immunohistochemical marker phosphohistone-H3 (PHH3) has been shown to be diagnostically useful, but its expression, in relation to outcome, has not been thoroughly investigated. The aim of this study is to evaluate PHH3 as a diagnostic and prognostic marker in USMTs. METHODS AND RESULTS: PHH3 expression was evaluated in 55 leiomyosarcomas (LMSs), 26 smooth muscle tumours of uncertain malignant potential (STUMPs), 18 leiomyomas with bizarre nuclei (LBN), and 12 leiomyomas (LMs). Scores were expressed as counts per 10 high-power fields (HPFs). Median follow-up durations of patients with LMS, STUMP, LBN and LM were, respectively, 39, 78, 65.5 and 49.5 months. Twenty-eight patients with LMSs (50.9%) died, and two (7.7%) patients with STUMPs experienced recurrence. The median PHH3 scores for LMSs were significantly higher than those for other categories of tumour. A score of ≥29/10 HPFs was also independently associated with a poor outcome. To test whether the PHH3 score could distinguish between benign USMTs with atypical histology and those that were clinically malignant, two biological groups were further delineated. Patients in group 1 (18 LBNs and 24 STUMPs) all had an uneventful outcome, whereas patients in group 2 (two recurrent STUMPs and 32 LMSs) all had a recurrence or tumour-related death. Median PHH3 scores for the two groups were, respectively, 2/10 HPFs and 27/10 HPFs. A PHH3 score of ≥7/10 HPFs was highly associated with malignancy. CONCLUSION: PHH3 is useful in evaluation of the biological behaviour of USMTs, and may serve as a prognostic indicator for LMSs.