Unveiling pembrolizumab effectiveness in diverse subtypes of MSI-high endometrial cancers.

OBJECTIVE: The efficacy of pembrolizumab in patients with microsatellite instability (MSI)-high cancers has been reported; however, the differences in efficacy according to the subtypes of MSI-high endometrial cancers (ECs) remain unclear. MSI-high ECs are classified into at least 3 groups based on their molecular characteristics: MLH1 hypermethylated, Lynch-like syndrome (LLS)-associated, and Lynch syndrome (LS)-associated cancers. This study aimed to investigate whether the efficacy of pembrolizumab differs among these 3 groups, and if so, whether EPM2AIP1 immunohistochemistry (IHC), which correlates with MLH1 promoter methylation, can be used to rule out MLH1 methylation cases. METHODS: This study included 12 patients with MSI-high EC who received pembrolizumab treatment. Patients were categorized into 3 groups based on MLH1 methylation analysis and the Amsterdam Criteria: MLH1 hypermethylated (sporadic [SP]), LLS-associated, and LS-associated. Patients' medical records were retrospectively reviewed, and the efficacy of treatment was evaluated based on the response rate using the Response Evaluation Criteria in Solid Tumors version 1.1. RESULTS: The overall response rate was 75% (3/4) in the SP group, while it was 100% including one complete response patient in the LLS-associated and the LS-associated group, respectively. The sensitivity and positive predictive value of EPM2AIP1 IHC for MLH1 methylation were 100% and 66.7%, respectively. CONCLUSION: Pembrolizumab may be more effective in LLS and LS-associated groups. EPM2AIP1 IHC was less predictive than MLH1 methylation analysis; however, it may be useful for ruling out MLH1 methylation cases due to its high sensitivity. Further studies are needed to determine whether EPM2AIP1 IHC can predict pembrolizumab efficacy.

Trop-2 expression and the tumor immune microenvironment in cervical cancer.

OBJECTIVE: Trophoblast Cell Surface Antigen 2 (Trop-2) is a transmembrane glycoprotein that is overexpressed in various cancers, with immunological significance as a target for tumor-reactive T-cells. We aimed to investigate the association between the expression of Trop-2 and the tumor immune microenvironment in cervical cancer. METHODS: The study included 123 patients with cervical cancer who underwent primary surgery between 2000 and 2020 in our hospital. Trop-2 expression was evaluated using anti-Trop-2 monoclonal antibody clone MAB650. Immune biomarkers, including PD-L1 (22C3), CD3 (PS1), and CD8 (4B11), were also evaluated. Trop-2 and PD-L1 positivity were defined by an H-score ≥ 10 and a combined positive score (CPS) ≥1, respectively. Tumor-infiltrating lymphocytes (TILs) were assessed in the five selected independent areas. The correlation between Trop-2 expression and immune biomarkers was analyzed. RESULTS: The cohort comprised patients with squamous cell carcinoma (SCC) (54.5%) and non-SCC (45.5%). Trop-2 was positive in 84.6% of samples and more commonly expressed in SCC (SCC vs. non-SCC; 97.0% vs. 69.6%, p < 0.001). Intratumoral CD3+ and CD8 + TILs were significantly more common in Trop-2-positive cases (CD3, Mann-Whitney U = 383, p < 0.0001; CD8, U = 442, p < 0.0001). Additionally, significant positive correlations were found between the Trop-2H-score and immune markers (CD3 + TILs, r = 0.295, p < 0.001; CD8 + TILs, r = 0.267, p = 0.001; PD-L1 CPS, r = 0.178, p = 0.025). No significant associations were detected between TILs and other clinicopathological features, including prognosis. CONCLUSION: Expression of Trop-2 in cervical cancer is associated with increased levels of intratumoral TILs, indicating the potential of Trop-2 targeted therapy alone or in combination with immune checkpoint inhibitors.

Predicting Trabectedin Efficacy in Soft Tissue Sarcoma: Inflammatory Biomarker Analysis.

BACKGROUND/AIM: Trabectedin is used as a treatment for advanced-stage soft tissue sarcomas (STSs), particularly liposarcoma and leiomyosarcoma. Aside from its direct effect on tumor cells, trabectedin can affect the immune system in the tumor microenvironment. This study aimed to evaluate whether inflammatory biomarkers predict trabectedin efficacy in STSs. PATIENTS AND METHODS: We retrospectively reviewed the clinical features and outcomes of patients with STS treated with trabectedin at our institution between 2016 and 2020. The neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), and systemic inflammation response index (SIRI=neutrophil × monocyte/lymphocyte) were calculated based on the blood samples obtained prior to trabectedin treatment initiation. Analyses of overall survival (OS) and progression-free survival (PFS) were performed according to various factors. RESULTS: Of the 101 patients identified, 54 had L-sarcoma (leiomyosarcoma: 30; liposarcoma: 24), and 47 had other types of STSs. Elevated SIRI, NLR, PLR, LMR, and C-reactive protein (CRP) were associated with worse PFS (p<0.001, p=0.008, p=0.027, p=0.013, and p<0.001, respectively) according to the results of the univariate analysis. Multivariate analysis showed that elevated SIRI, other histology, and CRP were associated with poor PFS (p=0.007, p=0.008, and p=0.029, respectively). In addition, the multivariate analysis of OS showed that SIRI was an independent prognostic factor (hazard ratio=2.16, p=0.006). CONCLUSION: Pretreatment SIRI can be considered a biomarker for the prognostic prediction of patients with STS treated with trabectedin.

Mesothelin expression in gynecologic carcinosarcoma: clinicopathological significance and correlation with HER2 expression.

OBJECTIVE: This study aimed to evaluate mesothelin (MSLN) expression and determine its clinical significance and correlation with human epidermal growth factor receptor 2 (HER2) expression in gynecological carcinosarcoma. METHODS: We retrospectively evaluated patients with uterine carcinosarcoma (UCS) and ovarian carcinosarcoma (OCS) who underwent surgery between 1997 and 2019. Immunohistochemical staining of formalin-fixed, paraffin-embedded specimens for MSLN (clone SP74) and HER2 (clone 4A5) was also performed. MSLN was scored using the H-score and 4-tired scoring system (0-3+). MSLN positivity was defined as any positive cell at any intensity, while high MSLN expression was defined as an intensity of ≥2+ in ≥30% of tumor cells. HER2 expression was scored according to modified 2018 American Society of Clinical Oncology/College of American Pathologists criteria. RESULTS: A total of 128 patients were recruited, including 119 with UCS and 9 with OCS. All cases in UCS exhibited MSLN positivity, and 33.9% showed high-MSLN expression. Clinicopathological characteristics were not significantly associated with high or low-MSLN expression. However, the high-MSLN group showed more prolonged overall survival (OS) than the low-MSLN group (not assessed vs. 36.8 months; hazard ratio=0.48, 95% confidence interval=0.26-0.89, p=0.016). HER2-high patients had higher MSLN expression than HER2-negative patients. In high-MSLN and low-MSLN expression groups, HER2 status did not affect OS. OCS showed 100% MSLN positivity, with 66.6% high-MSLN. CONCLUSION: MSLN expression is widely observed in gynecological carcinosarcomas. Moreover, high-MSLN expression is a favorable prognostic factor for UCS. MSLN could be a promising therapeutic target for UCS, even in the era of anti-HER2 therapy.

Durvalumab Plus Carboplatin/Paclitaxel Followed by Maintenance Durvalumab With or Without Olaparib as First-Line Treatment for Advanced Endometrial Cancer: The Phase III DUO-E Trial.

PURPOSE: Immunotherapy and chemotherapy combinations have shown activity in endometrial cancer, with greater benefit in mismatch repair (MMR)-deficient (dMMR) than MMR-proficient (pMMR) disease. Adding a poly(ADP-ribose) polymerase inhibitor may improve outcomes, especially in pMMR disease. METHODS: This phase III, global, double-blind, placebo-controlled trial randomly assigned eligible patients with newly diagnosed advanced or recurrent endometrial cancer 1:1:1 to: carboplatin/paclitaxel plus durvalumab placebo followed by placebo maintenance (control arm); carboplatin/paclitaxel plus durvalumab followed by maintenance durvalumab plus olaparib placebo (durvalumab arm); or carboplatin/paclitaxel plus durvalumab followed by maintenance durvalumab plus olaparib (durvalumab + olaparib arm). The primary end points were progression-free survival (PFS) in the durvalumab arm versus control and the durvalumab + olaparib arm versus control. RESULTS: Seven hundred eighteen patients were randomly assigned. In the intention-to-treat population, statistically significant PFS benefit was observed in the durvalumab (hazard ratio [HR], 0.71 [95% CI, 0.57 to 0.89]; P = .003) and durvalumab + olaparib arms (HR, 0.55 [95% CI, 0.43 to 0.69]; P < .0001) versus control. Prespecified, exploratory subgroup analyses showed PFS benefit in dMMR (HR [durvalumab v control], 0.42 [95% CI, 0.22 to 0.80]; HR [durvalumab + olaparib v control], 0.41 [95% CI, 0.21 to 0.75]) and pMMR subgroups (HR [durvalumab v control], 0.77 [95% CI, 0.60 to 0.97]; HR [durvalumab + olaparib v control] 0.57; [95% CI, 0.44 to 0.73]); and in PD-L1-positive subgroups (HR [durvalumab v control], 0.63 [95% CI, 0.48 to 0.83]; HR [durvalumab + olaparib v control], 0.42 [95% CI, 0.31 to 0.57]). Interim overall survival results (maturity approximately 28%) were supportive of the primary outcomes (durvalumab v control: HR, 0.77 [95% CI, 0.56 to 1.07]; P = .120; durvalumab + olaparib v control: HR, 0.59 [95% CI, 0.42 to 0.83]; P = .003). The safety profiles of the experimental arms were generally consistent with individual agents. CONCLUSION: Carboplatin/paclitaxel plus durvalumab followed by maintenance durvalumab with or without olaparib demonstrated a statistically significant and clinically meaningful PFS benefit in patients with advanced or recurrent endometrial cancer.

Therapeutic target biomarkers of patient-derived xenograft models of gastric-type cervical adenocarcinoma.

Background: Most cervical adenocarcinomas are associated with human papillomavirus (HPV). Gastric-type cervical adenocarcinoma (GAS), an HPV-independent adenocarcinoma, shows an aggressive clinical feature, resulting in a poor prognosis. Resistance to chemotherapy poses a difficulty in managing patients with metastatic GAS. We aimed to establish patient-derived xenografts (PDXs) of tumors from two patients with GAS and evaluated protein biomarkers for drug development using immunohistochemistry. Methods: Two PDXs were established 78 and 48 days after transplanting the patient's tumor tissues into immunodeficient mice, respectively. PDX and patient's tumor samples were stained for HER2, HER3, PMS2, MSH6, PanTrk, and ARID1A to evaluate biomarkers for therapeutic targets. In addition, whole exome sequencing and RNA sequencing were performed on available samples. Results: The pathological findings in morphological features and immunohistochemical profiles from the established PDXs were similar to those from the patients' surgical tumor specimens. HER3 was overexpressed in the patient's tumors, and the corresponding PDX tumors and HER2 was weakly stained in both types of tumor samples. In all PDX and patient tumor samples, PMS2, MSH6, and ARID1A were retained, and PanTrk was not expressed. In addition, a total of 10 samples, including tumor tissue samples from 8 other GAS patients, were evaluated for HER3 expression scores, all of which were 2 + or higher. Conclusions: In summary, we evaluated biomarkers for therapeutic targets using newly established PDX models of GAS. Frequent HER3 overexpression and HER2 expression in GAS tumors suggest the possibility of new treatments for patients with GAS by targeting HER3 and HER2.

Discordance in PD-L1 expression using 22C3 and SP142 assays between primary and metastatic triple-negative breast cancer.

AIMS: SP142 and 22C3 assays are approved companion diagnostic assays for anti-PD-1/PD-L1 therapy selection in metastatic triple-negative breast cancer (TNBC). The discordance in PD-L1 status between primary and metastatic tumors in the same patient has been poorly characterized. Here, we examined the concordance of PD-L1 status between the two assays and between primary tumors and metastases for each assay. METHODS: We retrospectively evaluated tumor samples from 160 patients with TNBC, including 45 patients with paired primary and metastatic tumors. PD-L1 status was assessed using SP142 and 22C3 assays, to determine the immune cell (IC) score, tumor cell (TC) score (SP142 and 22C3), and combined proportion score (CPS: 22C3). RESULTS: The concordance of PD-L1 positivity at diagnostic cutoffs for SP142 (IC ≥ 1) and 22C3 (CPS ≥ 10) was substantial (κ = 0.80) in primary tumors and moderate (κ = 0.60) in metastatic tumors. In comparison, between primary and metastatic tumors, the concordance with 22C3 was moderate (κ = 0.50), whereas that with SP142 was poor (κ = -0.03). Among patients who were PD-L1 negative for both assays in primary tumors, 7/30 (23.3%) were PD-L1 positive for both or either 22C3 or SP142 in the metastatic tumors. CONCLUSIONS: The inter-assay concordance of PD-L1 positivity at diagnostic cutoffs was substantial in primary tumors and moderate in metastatic tumors. Discordance between PD-L1 status in primary and metastatic tumors was frequently observed, especially with SP142. Some patients with a PD-L1-negative status in primary tumors may still be candidates for immunotherapy, depending on the PD-L1 status in their metastatic tumors.

Mismatch Repair Protein Expression in Endometrial Cancer: Assessing Concordance and Unveiling Pitfalls in Two Different Immunohistochemistry Assays.

This study aimed to compare the concordance and interchangeability of the Dako/Agilent and Ventana/Roche mismatch repair (MMR) immunohistochemistry (IHC) assays commonly used in pathology. It also aimed to provide diagnostic insights by examining the frequency and characteristics of the dot-like artifact observed in MLH1 M1 clone staining in endometrial cancer. Fifty endometrial cancer cases with MMR deficiency, excised between 2011 and 2018, were included in the study. IHC was performed using primary antibody clones from Ventana/Roche (MLH1, clone M1; MSH2, G219-1129; MSH6, SP93; PMS2, A16-4) and Dako/Agilent (MLH1, ES05; MSH2, FE11; MSH6, EP49; PMS2, EP51). Both assays were conducted using respective autostainers. The Dako/Agilent assay showed a loss of MLH1 in 26 cases, MSH2 in 12 cases, MSH6 in 23 cases, and PMS2 in 28 cases. The two assays had a complete agreement in MMR protein expression or loss. The dot-like artifact in MLH1 M1 clone staining was observed in 77% (20/26) of cases, predominantly in the surface area of the tumor, ranging from 5% to 40% (median: 10%). These findings highlight the high concordance between the MMR-IHC assays and emphasize the importance of considering the dot-like artifact in MLH1 M1 clone staining when diagnosing endometrial cancer with MMR deficiency.

Lymphocyte-to-monocyte ratio as a prognostic and potential tumor microenvironment indicator in advanced soft tissue sarcoma treated with first-line doxorubicin therapy.

Prognostic value of hematologic indices and their association with the tumor microenvironment (TME) remain unclear in advanced soft tissue sarcoma (STS). We aimed to evaluate their prognostic value and correlation with the TME status in advanced STS treated with first-line doxorubicin (DXR) therapy. Clinical data and three hematological indices, including lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio, and neutrophil-to-lymphocyte ratio, were collected from 149 patients with advanced STS. The TME status was pathologically examined by CD3, CD68, and CD20 staining of resected tumor slides. In a multivariate Cox analysis, low LMR and absence of primary tumor resection were independently associated with worse overall survival (OS) (HR 3.93, p = 0.001; HR 1.71, p = 0.03). A prognostic model using these variables predicted OS with greater area under curves than those obtained using Systemic Inflammatory Score and Glasgow Prognostic Score. The LMR significantly correlated with the tumoral CD3/CD68-positive cell ratio in surgical specimens (R = 0.959, p = 0.04). In conclusion, LMR was a prognostic factor in advanced STS treated with first-line DXR therapy. LMR could partially reflect anti-tumor immunity in the TME and have the prognostic value. The potential role of LMR as an indicator of TME status warrants further investigation.

Folate receptor alpha is widely expressed and a potential therapeutic target in uterine and ovarian carcinosarcoma.

OBJECTIVE: Folate receptor alpha (FRα), which is expressed in various cancers, is a potential therapeutic target. However, its expression and clinical significance in uterine (UCS) and ovarian carcinosarcoma (OCS) remain to be elucidated. METHODS: This retrospective study included patients with gynecologic carcinosarcoma who underwent primary surgery between 1997 and 2019 at our institution. Immunohistochemical staining of surgical FFPE specimens was performed for FRα and HER2. FRα was evaluated using the H-score and the 4-tired scoring system (0 to 3+). Subsequently, FRα expression (≥5% of tumor cells with ≥1+ intensity) and FRα-high (score 2+ and 3+) were evaluated. HER2 was scored according to the modified ASCO/CAP criteria. The association between FRα-high and clinicopathological features, HER2 expression, and survival was assessed in UCS. RESULTS: A total of 120 patients with UCS and nine patients with OCS were included. In UCS, FRα expression was observed in all patients, whereas FRα-high status was present in 20% of patients. Among HER2-negative UCS, 34% exhibited FRα-high. No significant association was observed between clinicopathological characteristics and FRα status. During the follow-up period (median 34.5 mo), FRα-high was not strongly associated with progression, free survival, and overall survival. All the OCS tumor specimens showed FRα-high expression. CONCLUSIONS: FRα expression was observed in all the UCS and OCS specimens, including HER2-negative UCS patients. This widespread FRα expression suggests that FRα-targeted therapies may hold promise for the treatment for gynecologic carcinosarcoma. However, in uterine carcinosarcoma, no significant relationship was observed between FRα expression and clinicopathological features or prognosis.

Development of a Detection System for ESR1 Mutations in Circulating Tumour DNA Using PNA-LNA-Mediated PCR Clamping.

Although circulating tumour DNA (ctDNA)-based next-generation sequencing (NGS) is a less invasive method for assessing ESR1 mutations that are essential mechanisms of endocrine therapy resistance in patients with oestrogen receptor-positive breast cancer, adequate amounts of DNA are required to assess polyclonal ESR1 mutations. By combining a peptide nucleic acid and locked nucleic acid polymerase chain reaction (PNA-LNA PCR) clamping assay, we have developed a novel detection system to screen for polyclonal ESR1 mutations in ctDNA. A validation assay was prospectively performed on clinical samples and compared with the NGS results. The PNA-LNA PCR clamp assay was validated using six and four blood samples in which ESR1 mutations were detected by NGS and no mutations were detected, respectively. The PNA-LNA assay results were comparable with those of NGS. We prospectively assessed the concordance between the PNA-LNA PCR clamp method and NGS. Using the PNA-LNA PCR clamp method, ESR1 mutations were detected in 5 out of 18 samples, including those in which mutations were not detected by NGS due to small amounts of ctDNA. The PNA-LNA PCR clamping method is a highly sensitive and minimally invasive assay for polyclonal ESR1 mutation detection in the ctDNA of patients with breast cancer.

Low HER2 expression is a predictor of poor prognosis in stage I triple-negative breast cancer.

Introduction: Triple-negative breast cancer (TNBC) is negative for hormone receptors and human epidermal growth factor receptor 2 (HER2). In stage I TNBC, adjuvant therapy or follow-up are performed according to risk factors, but clinical trial data is scarce. In recent years, it has been reported that HER2-low cases (1+/2+ and in situ hybridization negative) have different prognoses than HER2-0 cases. However, the risk of recurrence and risk factors in this HER2-low population for stage I TNBC have not yet been investigated. Methods: Herein, out of 174 patients with TNBC who underwent surgery from June 2004 to December 2009 at the National Cancer Center Hospital (Tokyo), we retrospectively examined 42 cases diagnosed as T1N0M0 TNBC after excluding those treated with preoperative chemotherapy. Results: All patients were female, the median age was 60.5 years, and 11 cases were HER2-low and 31 cases were HER2-0. The median follow-up period was 121 months. Postoperative adjuvant therapy was administered in 30 patients and recurrence occurred in 8 patients. HER2-low cases showed a significantly shorter disease-free survival (HR: 7.0; 95% CI: 1.2- 40.2; P=0.0016) and a trend towards shorter overall survival (hazard ratio [HR]: 4.2, 95% confidence interval [CI]: 0.58-31.4) compared with that of HER2-0 cases. HER2 was also identified as a factor for poor prognosis from the point- estimated values in univariate and multivariate analyses after confirming that there was no correlation between the other factors. Conclusion: For patients with stage I TNBC, the HER2-low population had a significantly worse prognosis than the HER2-0 population.

Discordances in expression of human epidermal growth factor receptor 2 between primary and metastatic uterine carcinosarcoma: A proposal for HER2-targeted therapy specimen selection.

Uterine carcinosarcoma (UCS) frequently expresses human epidermal growth factor receptor 2 (HER2) and metastasizes. However, little is known about changes in the HER2 expression status in metastatic lesions and its impact on clinical outcomes. In 41 patients with synchronous or metachronous metastases and matched primary UCSs, we assessed the HER-2 expression using immunohistochemistry and scored it per the 2016 American Society of Clinical Oncology/College of American Pathologists guidelines, modified for UCS. We compared HER2 scores between paired primary and metastatic lesions and reviewed the association between clinicopathological characteristics and impact on overall survival. HER2 scores of 3+, 2+, 1+, and 0 were observed in 12.2 %, 34.2 %, 26.8 %, and 26.8 % of primary tumors, respectively, and 9.8 %, 19.5 %, 43.9 %, and 26.8 % of metastatic tumors, respectively. HER2 intratumoral heterogeneity occurred in 46.3 % and 19.5 % of the primary and metastatic lesions, respectively. The agreement rate of the HER2 score was 34.2 % in the four-tiered scale, while it was 70.7 % in the two-tiered scale (score 0 vs. score ≥ 1+) with fair agreement (к = 0.26). Patients with HER2 discordance showed significantly shorter overall survival (hazard ratios = 2.38, 95 % confidence interval 1.01-5.5, p = 0.049). HER2 discordance was not associated with specific clinicopathological characteristics. Discordance in HER2 status between primary and metastatic tumors in UCS was frequently observed regardless of clinicopathological characteristics and was a poor prognostic factor. Even if one tumor (primary or metastatic) is HER2 negative, HER2 testing of other tumors may be beneficial in terms of patient treatment options.

A case of vasculogenic mesenchymal tumor in the mediastinum: whole-exome sequencing reveals origin from pre-existing germ cell tumor.

Vasculogenic mesenchymal tumor (VMT), a primitive mesenchymal neoplasm enriched by various-sized atypical vessels, is a new entity that develops in mediastinal germ cell tumors (GCTs) with yolk sac tumor (YST) components after chemotherapy. Notably, patients with VMT in the residual GCT have increased risk of developing sarcomas or hematopoietic malignancies. Here, we report a late-teenage male patient with residual teratoma and high-grade VMT after chemotherapy for a mediastinal mixed GCT, including YST. Whole-exome sequencing revealed biallelic inactivation of TP53 and extensive copy number alterations that suggested whole-genome doubling. The biopsy tissue of the mixed GCT before chemotherapy exhibited overlapping genetic alterations to those in the VMT. Immunohistochemical analyses of the VMT showed that the abnormal vessels were positive for cytokeratin, glypican 3, EZH2, and IMP3. The findings that VMT inherits the genetic alterations of pre-existing mixed GCT and exhibits a partly YST-like immunophenotype might contribute to its clinical aggressiveness.

Co-Clinical Study of [fam-] Trastuzumab Deruxtecan (DS8201a) in Patient-Derived Xenograft Models of Uterine Carcinosarcoma and Its Association with Clinical Efficacy.

PURPOSE: Uterine carcinosarcoma (UCS), a subtype of endometrial carcinoma, is a rare and aggressive cancer with a poor prognosis. High clinical efficacy of trastuzumab deruxtecan (T-DXd) in HER2-expressing UCS was recently reported in a phase II trial (STATICE trial). We performed a co-clinical study of T-DXd using patient-derived xenograft (PDX) models of participants in the STATICE trial. EXPERIMENTAL DESIGN: Tumor specimens were resected during primary surgery or biopsied at recurrence from patients with UCS and transplanted into immunodeficient mice. Seven UCS-PDXs from six patients were established and HER2, estrogen receptor (ER), and p53 expression in PDX and the original tumor was assessed. Drug efficacy tests were performed using six of the seven PDXs. Of the six UCS-PDXs tested, two were derived from patients enrolled in the STATICE trial. RESULTS: The histopathological characteristics of the six PDXs were well-conserved from the original tumors. HER2 expression was 1+ in all PDXs, and ER and p53 expression was almost similar to that in the original tumors. Remarkable tumor shrinkage after T-DXd administration was observed in four of the six PDXs (67%), comparable with the response rate (70%) of HER2 1+ patients in the STATICE trial. Two patients enrolled in the STATICE trial showed partial response as the best response, and the clinical effect was well-replicated with marked tumor shrinkage. CONCLUSIONS: We successfully performed a co-clinical study of T-DXd in HER2-expressing UCS, along with the STATICE trial. Our PDX models can predict clinical efficacy and serve as an effective preclinical evaluation platform.

Trastuzumab Deruxtecan for Human Epidermal Growth Factor Receptor 2-Expressing Advanced or Recurrent Uterine Carcinosarcoma (NCCH1615): The STATICE Trial.

PURPOSE: To investigate the efficacy and safety of trastuzumab deruxtecan, an antibody-drug conjugate targeting human epidermal growth factor receptor 2 (HER2) with a topoisomerase I inhibitor payload, in patients with uterine carcinosarcoma (UCS) expressing HER2. PATIENTS AND METHODS: Patients with recurrent UCS with HER2 immunohistochemistry scores ≥1+ previously treated with chemotherapy were included. Patients were assigned to the HER2-high (immunohistochemistry score ≥2+; n = 22) or low (immunohistochemistry score of 1+; n = 10) groups for primary and exploratory analyses, respectively. Trastuzumab deruxtecan 6.4 or 5.4 mg/kg was administered intravenously once every 3 weeks until unacceptable toxicity or disease progression. Dose modification was based on the updated recommended phase II dose for breast cancer to be 5.4 mg/kg. The primary end point was the objective response rate by central review in the HER2-high group. Secondary end points included the overall response rate (ORR) in the HER2-high group by investigator assessment, ORR in the HER2-low group, progression-free survival (PFS), overall survival (OS), and safety. RESULTS: The ORR by central review in the HER2-high and HER2-low groups were 54.5% (95% CI, 32.2 to 75.6) and 70.0% (95% CI, 34.8 to 93.3) and those by investigator assessments were 68.2% and 60.0%, respectively. The median PFS and OS in the HER2-high and HER2-low groups were 6.2 and 13.3 months and 6.7 months and not reached, respectively. Grade ≥ 3 adverse events occurred in 20 patients (61%). Grades 1-2 and 3 pneumonitis/interstitial lung disease occurred in eight (24%) and one (3%) patient, respectively. CONCLUSION: Trastuzumab deruxtecan has efficacy in patients with UCS, regardless of HER2 status. The safety profile was generally consistent with that previously reported. Toxicities were manageable with appropriate monitoring and treatment.

Changes in HER3 expression profiles between primary and recurrent gynecological cancers.

BACKGROUND: Human epidermal growth factor receptor-3 (HER3) is a member of the epidermal growth factor receptor family of receptor tyrosine kinases, and its overexpression is associated with inferior prognosis in several cancers. However, it is unclear whether HER3 expression status changes in tumor tissue at recurrence. Therefore, this study aimed to evaluate the changes in HER3 expression between primary and recurrent status in gynecological cancers. METHODS: This retrospective study used matched-pair tissues of gynecological cancer patients at initial diagnosis and at recurrence. Immunohistochemical (IHC) scores of 3 + or 2 + were termed "HER3-high", while IHC scores of 1 + or 0 were designated as "HER3-low/zero". RESULTS: A total of 86 patients (40 with ovarian cancers, 32 with endometrial cancers, and 14 with cervical cancers) were included in this study. In ovarian cancer, 67.5% and 80.0% of the patients received a HER3-high at initial and recurrent diagnosis, respectively. The H-score was significantly increased at recurrence (p = 0.004). The proportion of HER3-high endometrial cancer patients increased from 46.9% at initial diagnosis to 68.8% at recurrence, and the H-score tended to increase at recurrence (p = 0.08). The fraction of HER3-high-rated cervical cancer patients remained unchanged at 85.7% both at initial and recurrent diagnosis. The discordance rate of HER3 expression detection in initial and recurrent diagnosis samples was 27.5%, 53.1%, and 14.3% for ovarian, endometrial, and cervical cancers, respectively. Ovarian and endometrial cancers with a HER3-high recurrent score tended to show shorter median survival time than those with a HER3-low/zero recurrent rating. CONCLUSION: Our findings suggest that, in main types of gynecological cancers, the proportion of patients having a HER3-high score increased from initial to recurrent diagnosis.

Impact of adjuvant chemotherapy and radiotherapy on tumour-infiltrating lymphocytes and PD-L1 expression in metastatic breast cancer.

BACKGROUND: Chemotherapy and radiotherapy were postulated to induce an inflamed tumour microenvironment. We aimed to evaluate the effects of adjuvant chemotherapy/radiotherapy on tumour-infiltrating lymphocytes (TILs) and programmed death-ligand 1 (PD-L1) expression in metastatic breast cancer. METHODS: We identified paired primary and metastatic tumours in 85 patients with breast cancer. Stromal TILs were assessed according to international guidelines. PD-L1 expression was evaluated using the VENTANA SP142 assay. RESULTS: TILs were significantly lower in metastatic tumours than in primary tumours (12.2 vs. 8.3%, p = 0.049). PD-L1 positivity was similar between primary and metastatic tumours (21.2 vs. 14.1%, p = 0.23). TILs were significantly lower in patients who received adjuvant chemotherapy than in those who did not (-9.07 vs. 1.19%, p = 0.01). However, radiotherapy had no significant effect on TILs (p = 0.44). Decreased TILs predicted worse post-recurrence survival (hazard ratio, 2.94; 95% confidence interval [CI]: 1.41-6.13, p = 0.003), while increased TILs was associated with a better prognosis (HR, 0.12; 95% CI: 0.02-0.08, p = 0.04). CONCLUSIONS: TILs decreased in metastatic tumours, particularly in patients who relapsed after adjuvant chemotherapy. Changes in TILs from primary to metastatic sites could be a prognostic factor after recurrence.

Uterine Leiomyosarcoma Masquerading as a Malignant Perivascular Epithelioid Cell Tumor: A Diagnostic Challenge.

Uterine sarcomas with myomelanocytic differentiation have been reported to be diagnostically challenging. We report a case of uterine leiomyosarcoma with extensive perivascular epithelioid cell tumor (PEComa)-like areas and extrauterine metastases. The patient was a 49-year-old gravida 3 para 2 Japanese woman with no relevant medical history. She noticed a vaginal mass with bleeding. Imaging examination revealed a uterine tumor and multiple liver and lung metastases. The vaginal tumor (3.5 cm) was resected and diagnosed as a malignant PEComa based on morphology and myomelanocytic marker expression. Clinically used targeted sequencing (FoundationOneCDx™) revealed gene alterations in RB1, TP53, and ATRX but not TSC1/2. Despite administration of an mTOR inhibitor, the tumor size increased, and subsequently, hysterectomy was performed to relieve the symptoms. The uterine tumor was composed of conventional leiomyosarcoma showing RB1 loss, wild-type TP53 staining, and retained ATRX expression, as well as adjacent predominant PEComa-like components with RB1 loss, TP53 overexpression, and ATRX loss, identical to the characteristics of the vaginal tumor. In the uterine tumor, both HMB-45 and MITF were weak to moderately positive for approximately 40% of tumor cells while Melan-A was negative. The tumor was finally diagnosed as leiomyosarcoma with PEComa-like features. This case exemplifies the tumorigenesis of diagnostically challenging tumors with myomelanocytic differentiation and demonstrates the importance of integrating multiple types of information, including genomic profiling, in making a correct diagnosis leading to appropriate treatment.

Integrative prognostic analysis of tumor-infiltrating lymphocytes, CD8, CD20, programmed cell death-ligand 1, and tertiary lymphoid structures in patients with early-stage triple-negative breast cancer who did not receive adjuvant chemotherapy.

PURPOSE: Stromal tumor-infiltrating lymphocytes (TILs) are independent prognostic factors in systemically untreated early-stage triple-negative breast cancer (TNBC). Other immune biomarkers including CD8, CD20, programmed cell death-ligand 1 (PD-L1), and tertiary lymphoid structures (TLS) are also reported to be associated with prognosis. However, whether combining other immune biomarkers with TILs would allow for further prognostic stratification is unknown. METHODS: We retrospectively analyzed 125 patients with early-stage TNBC not receiving perioperative chemotherapy. Stromal TILs and TLS were evaluated on hematoxylin-eosin slides. PD-L1 expression was evaluated using the SP142 assay. CD8 and CD20 were assessed by immunohistochemistry and counted by digital pathology. RESULTS: Immune biomarker levels were positively correlated (p < 0.001). Adding CD8 and PD-L1 to multivariable analysis including clinicopathological factors (stage and histological grade) and TILs significantly improved the prognostic model (likelihood ratio χ2 = 9.24, p = 0.01). In Cox regression analysis, high CD8 was significantly associated with better prognosis [hazard ratio (HR) 0.69, 95% confidence interval (CI) 0.48-0.98, p = 0.04], and PD-L1 positivity was significantly associated with worse prognosis (HR 4.33, 95%CI 1.57-11.99, p = 0.005). Patients with high CD8/PD-L1 (-) tumors had the most favorable prognosis [5 year invasive disease-free survival (iDFS), 100%], while patients with low CD8/PD-L1( +) tumors had the worst prognosis (5 year iDFS, 33.3%). CONCLUSION: CD8 and PD-L1 levels add prognostic information beyond TILs for early-stage TNBC not receiving perioperative chemotherapy. CD8-positive T cells and PD-L1 may be useful for prognostic stratification and in designing future clinical trials of TNBC.