Residual Tumor Cells Research Articles

A phase 2 study of de-escalation in resectable, locally advanced cutaneous squamous cell carcinoma (cSCC) with the use of neoadjuvant pembrolizumab: De-Squamate.

9514 Background: Neoadjuvant anti-Programmed Death therapy has shown a 64% complete or major pathological response rate in patients (pts) with resected stage II-IV(M0) cSCC. The De-Squamate study (NCT05025813) evaluated the feasibility of a risk adapted surgical de-escalation approach guided by clinical, radiological and pathological response in resectable cSCC pts of all sites receiving neoadjuvant pembrolizumab. Methods: This multi-centre, open-labelled, non-randomised, single-arm phase 2 study evaluated the response of neoadjuvant Pembrolizumab for 4 cycles administered IV 200mg Q3W in immunocompetent pts with Stage II-IV (M0) resectable cSCC. Pts underwent CT/MRI and 18F-FDG-PET imaging at baseline and following completion of neoadjuvant pembrolizumab. In those with a complete metabolic response, mapping biopsies of target site(s) were performed and if negative for residual SCC (clinical complete response [CCR]), surgery and post operative radiation therapy (PORT) were omitted. Patients with clinical or radiological residual disease/ positive mapping biopsy underwent surgical resection. PORT was de-escalated if there was a pathological complete response (PCR - no residual tumour cells) or major pathological response (MPR - less than or equal to 10% viable tumour cells). Pts proceeded to 13 cycles of maintenance Pembrolizumab. The primary endpoint was the combined rate of PCR, MPR and CCR following neoadjuvant Pembrolizumab and secondary endpoint includes treatment de-escalation and safety. Results: All 27 patients were enrolled and received a minimum of 2 cycles of neoadjuvant Pembrolizumab. The primary endpoint was observed in 17 patients (63%, 95% CI: 42-80), comprised of PCR (15%), MPR (0%) and CCR (48%). De-escalation of both surgery and PORT was achieved in 48% and a further 15% avoided PORT alone. With a minimum follow up of 6 months, no pts with PCR/MPR/CCR recurred. Investigator assessed treatment-related adverse events ≥ grade 3 was seen in 2 patients (7%). Conclusions: Pembrolizumab led to a high rate of PCR and CCR in resectable cSCC. The de-squamate study design effectively selected pts for surgical and PORT de-escalation and demonstrated a sustained response in this cohort. Clinical trial information: NCT05025813 .

Pathologic examination of specimen after vacuum-assisted biopsy (VAB) in patients with breast cancer after neoadjuvant systemic therapy (NST).

e12589 Background: VAB of the tumor bed in the breast has shown promising results as a minimally invasive method for determining pathologic complete response (pCR). A significant disadvantage of VAB is the fragmentation of the obtained material and the lack of methods for determining generally accepted predictive and prognostic factors such as RCB index in case if residual tumor is detected. Here we present a description of the accumulated experience of histological examination of specimens obtained using VAB in patients with breast cancer after NST. Methods: A single-center, prospective, non-randomized study included patients with unifocal breast cancer (cT1–2N0–1M0). Patients who achieved a complete clinical response (cCR) underwent VAB. VAB specimen intraoperatively was divided into «inner contour» (first 6-12 samples) and «outer contour» (latter 6-12 samples). Patients without signs of residual tumor (pCR, ypT0N0) did not undergo further surgical intervention. In case if residual tumor cells (RTC) were detected, standard breast surgery was performed. To assess an extent of tumor response to NST instead of RCB we used Miller-Payne system which has correlation with RCB. Results: 35 patients with a mean age of 48.3 (31–67) years were included in the analysis. Examination of VAB samples showed that 11 (31.4%) patients had a residual tumor, and in 24 (68.6%) patients no tumor cells were detected (ypT0N0). According to the Miller-Payne system, 28 patients had a complete pathological response, which corresponds to Miller-Payne = 5 and pathological stage ypT0/ypTis (24 patients ypT0N0, 3 patients ypTisN0 and 1 patient ypT0N1). In 7 patients with residual invasive tumor, the tumor response according to the Miller-Payne scale corresponded to grades 3 and 4. There was a statistically significant correlation between presence of RTC in the «outer contour» of VAB and presence of RTC in the postoperative histology after standard surgery (Х2 p=0.01, Fisher exact test p=0.048). In case when RTC were found in the «inner contour» no correlation with the presence of RTC in the postoperative histology after standard surgery was observed (Х2 p=0.292, Fisher exact test p=1.0). Radiologic-pathologic discordance was 25% for mammolymphoscintigraphy, 35.5% for US and 39.4% for mammography. In case if 3 of 3 studies after NST described cCR radiologic-pathologic discordance was 16.7%, in case if 2 of 3 studies described cCR it was 22.2% and in case if only 1 of 3 studies described cCR it was 27.3%. Conclusions: The method used to evaluate histological material allows us to obtain predictive and prognostic information necessary to clarify further treatment tactics in accordance with modern standards. It is necessary to conduct large-scale studies in this area to answer the question if this method can be used in routine clinical practice. Clinical trial information: NCT04293796 .

EGFR-TKI as neoadjuvant treatment in patients with NSCLC with EGFR sensitive mutation: A retrospective real-world analysis.

8081 Background: This study aimed to evaluate the efficacy and outcome of Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) as preoperative neoadjuvant treatment in patients with NSCLC and EGFR sensitive mutation. Methods: A retrospective analysis was conducted. Patients with resectable stage I-III NSCLCs and received neoadjuvant treatment with any generation of EGFR-TKI before surgical resection were enrolled. The primary endpoint were major pathological response (MPR) and objective response rate (ORR), the second endpoints included diseases down staging, surgical outcomes, disease-free survival (DFS) and overall survival (OS). Results: A total of 58 patients were enrolled. Female accounted for 62.1% and most of them (77.6%) were never-smoker. Forty-five (77.6%) patients received the first generation of EGFR-TKI and 11 received the third. The median duration of EGFR-TKI before surgery was 3.6 months (0.7-19.5m). Nine (15.5%) patients achieved MPR and one patient (1.71%) achieved pathological complete response (pCR). The ORR was 60.3% (35/58) according to RECIST v1.1. Eighteen patients achieved TNM downstaging with T downstaging occurred in 44.8% of patients and N downstaging was about 32.8%. Majority of patients (96.6%) underwent thoracoscopic surgery and the rate of R0 resection was 82.8% (48/58). The DFS and OS of the whole cohort was 25.7months and not reached respectively. Patients with MPR had statistically improved outcomes than those without. What noticeable was that patients with tumor regression grade 3 (13/58) (residual viable tumor cells counts for 10% to 50%) also demonstrated a significant benefit from EGFR-TKI preoperative treatment than those with TRG4 or 5 (residual viable tumor cells>50%) (p = 0.01). We define patients with TRG1 to TRG3 as deep pathological regression (DPR) and the rest as non-DPR, and the DPR cohort showed significantly prolonged DFS than those with non-DPR (median DFS, 60.9 vs 16.7 months; HR, 0.29 (95%CI: 0.11-0.74), p = 0.006), the data of OS was not mature. Subgroup analysis validated DPR was an independent predictive factor for DFS. Conclusions: EGFR-TKI as neoadjuvant therapy had good effect on tumor pathological regression and disease downstaging, DPR patients were more likely to achieve long-term disease-free survival. Patients with NDPR should be closely followed up and appropriate adjuvant therapy was necessary after surgery due to the high risk of reccurence.

An NCDB analysis of the predictive factors associated with the receival of tumor resection in mucinous cystadenoma of the pancreas.

e16356 Background: Mucinous cystadenoma (MCN) of the pancreas is characterized by mucin-producing cystic tumors that may lead to pancreatic ductal obstruction. While many of these cystic lesions are benign, there exists a notable risk for malignancy. Presently, the standard approach to managing MCN involves surveillance. Surgical resection is considered after evaluating histological features, the patient's age, surgical risk, and tumor size. Previous studies have linked surgical resection to favorable overall outcomes. However, no studies have investigated the predictive factors correlated to receiving surgery in MCN patients. This study aims to utilize the National Cancer Database (NCDB) to analyze factors that determine receival of tumor resection in patients with MCN of the pancreas. Methods: The NCDB was used to identify patients diagnosed with MCN of the pancreas from 2004 to 2019 using the histology codes 8470 as assigned by the Commission on Cancer Accreditation program. Kaplan-Meier, ANOVA Chi-Square, and Multilevel Logistic Regression were performed, and data were analyzed using SPSS version 27. Statistical significance was set at α = 0.05. Results: 827 patients with MCN of the pancreas formed the initial sample. 552 patients received a tumor resection whereas 274 patients did not receive surgery ( 66.7% vs 33.1%, respectively). Surgical patients experienced significantly longer overall survival than nonsurgical patients ( 111.2 months vs. 20.1 months, p < 0.001). Complete tumor resection with no residual tumor cells was associated with improved outcomes in MCN( p < 0.001). Metastasis to distant sites was associated with decreased likelihood of receiving surgery ( p < 0.001). Well and moderately differentiated disease, stage I, II, and II disease, treatment at an academic facility, and private insurance status were associated with increased likelihood of receiving tumor resection ( p < 0.001). Income status and race did not appear to impact overall survival of these patients. Adjuvant therapies did not appear to impact overall survival of these patients. Conclusions: The results of this research align with other studies, affirming that surgical resection yields superior outcomes in patients with MCN of the pancreas. Factors such as well or moderately differentiated disease, early-stage diagnosis, treatment at academic facilities, and private insurance status increased the likelihood of tumor resection. Distant metastasis reduced the likelihood of receiving surgery. Complete tumor removal without presence of residual tumor cells post-surgery is correlated with improved survival. Income status and race did not appear to impact overall survival, and adjuvant therapies showed no discernible effect. To improve current treatment protocols for patients with MCN of the pancreas, more research needs to be conducted on the predictive factors of receiving surgery.

Trifluridine/Tipiracil Based Chemoradiation in locally Advanced Rectal Cancer: The Phase I/II TARC Trial

BackgroundOptimizing functional outcomes and securing long-term remissions are key goals in managing patients with locally advanced rectal cancer. In this proof-of-concept study, we set out to further optimize neoadjuvant therapy by integrating the radiosensitizer trifluridine/tipiracil and explore the potential of cell free tumor DNA (ctDNA) to monitor residual disease. MethodsAbout 10 patients were enrolled in the phase I dose finding part which followed a 3 + 3 dose escalation design. Tipiracil/trifluridine was administered concomitantly to radiotherapy. ctDNA monitoring was performed before and after chemoradiation with patient-individualized digital droplet PCRs. ResultsNo dose-limiting toxicities were observed at the maximum tolerated dose level of 2 × 35 mg/m² trifluridine/tipiracil. There were 9 grade 3 adverse events, of which 8 were hematologic with anemia and leukopenia. Chemoradiation yielded a pathological complete response in 1 out of 8 assessable patients, downstaging in nearly all patients, and 1 clinical complete response referred for watchful waiting. Three of 4 assessable patients with residual tumor cells at pathological assessment remained liquid biopsy positive after chemoradiation, but 1 turned negative. ConclusionIn this exploratory phase I trial, the novel combination of neoadjuvant trifluridine/tipiracil and radiotherapy proved to be feasible, tolerable, and effective. However, the application of liquid biopsy as a potential marker for therapeutic de-escalation in the neoadjuvant setting requires additional research and prospective validation.The trial was registered at ClinicalTrials.gov: NCT04177602.

Neoadjuvant adebrelimab plus dalpiciclib in HPV-negative locally advanced head and neck squamous cell carcinoma: A phase II clinical trial.

TPS6129 Background: The efficacy and safety of neoadjuvant immunotherapy (NAI) for treating resectable locally advanced head and neck squamous cell carcinoma (LAHNSCC) remain uncertain, and the comprehensive protocol of NAI needs further explored. The tumor suppressor gene CDKN2A plays a pivotal role in cell cycle regulation by modulating cyclin-dependent kinase (CDK) activity. Mutations in CDKN2A lead to continuous activation of CDK4/6, resulting in uncontrolled cell proliferation and tumor growth. Approximately 35.7% of HNSCC patients exhibit CDKN2A mutations, with the incidence rising to 58% among HPV-negative LAHNSCC patients. Studies have shown that combining immunotherapy with a CDK4/6 inhibitor produces a synergistic anti-tumor effect. This study aims to assess the efficacy and safety of combining anti-PD-L1 (adebrelimab) with a CDK4/6 inhibitor (dalpiciclib) as NAI in resectable LAHNSCC patients. Methods: This open-label, single-arm, prospective phase II trial will enroll LAHNSCC patients eligible for surgery. Inclusion criteria include: being 18 to 75 years old at study entry; pathologically confirmed HPV-negative HNSCC (oral, laryngeal, hypopharyngeal, and HPV-negative oropharyngeal carcinoma), determined via p16 immunohistochemistry or HPV DNA tests; with CDKN2A mutation; resectable LAHNSCC, staged III-IVB according to the UICC/AJCC 8th edition TNM system; an ECOG Performance Status score of 0 or 1; no prior relevant anti-tumor treatments; intent for curative treatment; and adequate organ function. Key exclusion criteria are active autoimmune diseases, use of immunosuppressive drugs, or systemic corticosteroids. Eligible patients receive 3 cycles of adebrelimab (1200 mg intravenously every 3 weeks, Day 1, 22 and 43) and 2 cycles of dalpiciclib (150 mg, po, every 4 weeks, day 1-21 and 29-49) before surgery. Dose adjustments are allowed based on toxicity. Surgery will follow 2-4 weeks post-NAI, with subsequent adjuvant radiotherapy or chemoradiotherapy based on risk factors after surgery. The primary endpoints are 1-year disease-free survival (defined as the time from surgical resection to local recurrence) and major pathological response (MPR, defined as ≤10% residual viable tumor cells), with secondary endpoints focusing on safety and predictive biomarkers. Clinical trial information: NCT06199271 .

Multiplex analysis of the immune environment before and after neoadjuvant durvalumab as a prognostic factor in resectable non-small cell lung cancer (NSCLC) in the IFCT-1601 IONESCO phase 2 trial.

8022 Background: Immune checkpoint inhibitors (ICI) are currently included in the peri-operative standard of care for NSCLC with the objective of a curative strategy. In early stages of NSCLC, biomarkers predicting ICI efficacy should be more stringent than PD-L1 tumoral expression in order to improve the benefit-toxicity ratio. We deeply analyzed the tumor microenvironment of patients included in the IONESCO multicenter phase 2 trial (stage IB > 4cm–IIIA, non N2 resectable NSCLC). Diagnostic biopsies and surgical resection specimen after 3 cycles of Durvalumab were available. We previously showed that the % of residual viable tumor cells (RVT) was associated with disease free survival (DFS) and overall survival (OS). PD-L1 tumor positive score was not correlated to RVT nor survival. Methods: 46 patients were included in the IONESCO trial. Among them, diagnostic biopsy (n = 32), surgical resection specimen post durvalumab (n = 39) and paired tumor samples (n = 31) were analyzed. Immune environment was assessed using 7 quantitative 7-plex immunofluorescence panels generating 349 different cellular phenotypes in 3 different compartments (whole tumor, intra cytokeratin and stroma), focusing on T and B lymphocytes, macrophages, immune checkpoint, NK cells, apoptosis, innate and adaptive immunity, dendritic cells. Densities of cells were quantified using Fluorescent Multiplex immunohistochemistry performed on Leica Bond RX, using OpalTM technology. A fisher's exact test or chi2 test was used for demographics variables and RVT. HRs and 95% CIs were estimated using a Cox model. NCT number: NCT03030131. Results: With median follow-up of 4.5 years, 16/31 patients had a disease recurrence. Histology, sex, stage and survival were significantly associated with intra-tumor densities of CD3, CD8, PD1, TIM3, and CD163 cells in the diagnostic biopsy, and with the delta of CD3, FoxP3, CD4, CD163PD1, TIM3, PDL1 on immune cells and TIM3PDL1 cells, between biopsy and surgical specimen. DFS was significantly associated with high density of CD8+TIM3+ in biopsies (HR = 0.25 [0.09-0.71], p = 0.0092) and with the high density of CD20+ cells in surgical specimen (HR = 0.36 [0.13-0.97], p = 0.04). The RVT was significantly associated with CK+Caspase3- cells and CK+PDL1+ cells in the surgical specimen. No biomarker was associated with OS. Conclusions: Multiparameter analysis of the immune NSCLC environment of patients treated with neoadjuvant anti-PDL1 allows identification of markers associated with clinical, pathological parameters and DFS. Our findings highlight the substantial impact of high CD8+TIM3+ cell density pre-durvalumab and of high CD20+ cell density post-durvalumab on DFS. These findings deserve to be assessed in patients treated with neoadjuvant combined immunotherapy chemotherapy. Clinical trial information: NCT03030131 .

Neoadjuvant immunochemotherapy and new radiomic predictor for resectable locally advanced oral squamous cell carcinoma.

6090 Background: The effectiveness of neoadjuvant immunochemotherapy (NAIC) in treating resectable locally advanced oral squamous cell carcinoma (LAOSCC) remains uncertain, with a notable lack of precise prognostic markers for NAIC outcomes. Methods: A single-arm prospective phase II trial was performed to assess the efficacy and safety of NAIC, consisting of 2 cycles of intravenous camrelizumab (200 mg), albumin paclitaxel (260 mg/m²), and cisplatin (75 mg/m²) administered every 3 weeks prior to radical surgery in LAOSCC patients. Adjuvant radiotherapy or chemoradiotherapy was determined by post-surgical pathology. Patients with previously untreated, stage III-IVB LAOSCC (the 8th edition of UICC/AJCC staging system), aged 18-75 years were enrolled. The primary endpoints were major pathological response (MPR, defined as ≤10% residual viable tumour (%RVT) cells) and safety, the second primary point was objective response rate (ORR) according to RECIST 1.1. To identify potential radiomic markers predictive of NAIC benefit, oscillating-gradient spin-echo (OGSE) magnetic resonance imaging sequences were obtained before and after NAIC. Results: From Feb 1, 2023 to Jan 1, 2024, 30 patients were enrolled, among which, 26 patients have received NAIC followed by surgery. The MPR rate was 65.4% (17/26), including a 34.6% (9/26) pathological complete response. Patients with PD-L1 (Combined Positive Score) ≥ 1 had higher MPR (80.0%, 16/20) than those with PD-L1 < 1 (16.7%, 1/6). NAIC was well-tolerated, without adverse effects on subsequent surgery, only two patients experienced grade 3 or 4 adverse events during NAIC, including one with grade 4 neutropenia (3.8%), and one with grade 3 thrombocytopenia (3.8%). The ORR was 80.8% (21/26), with 15.4% (4/26) complete response, 65.4% (17/26) partial response, and with no cases of progressive disease observed. The mean cell diameters of the whole tumor were calculated based on the OGSE sequences, twenty patients completed the OGSE scaning pre- and post-NAIC treatment. Pearson correlation analyses found that small post-NAIC mean cell diameter significantly related with fewer %RVT ( p = 0.026), supporting its potential as new radiomic predictors of NAIC efficacy. Among patients with MPR, the cell diameters were significantly decreased after NAIC, with a mean cell diameter of 18.87 ± 2.49 μm and 14.77 ± 1.85 μm for pre- and post-NAIC tumor, respectively ( p = 0.001). Conclusions: Camrelizumab combined with albumin paclitaxel/cisplatin as NAIC for LAOSCC demonstrates promising MPR and well safety. Mean cell diameter of tumor, derived from OGSE sequences, emerges as a potential new radiomic marker for predicting NAIC efficacy. Ongoing follow-ups on long-term survival and the development of a bio-radiomic prediction model integrating pathological features with OGSE data are underway. Clinical trial information: ChiCTR2200066119.

Neoadjuvant aromatase inhibitor therapy for ER+ breast cancer: The NAOMI trial.

e12646 Background: Neoadjuvant Endocrine Therapy (NET) is an effective and well tolerated treatment for locally advanced ER+ breast cancer (BC) yet it is underutilized. It can induce comparable clinical response rates to chemotherapy but not pathologic complete response. There is a knowledge gap regarding its effect on residual cancer cells and fatty acid oxidation which is essential for survival of dormant ER+BC cells after estrogen withdrawal in vitro. The NAOMI trial is a study testing the effects of NET with the AI letrozole in early ER+ BC. It aimed to assess the effect of letrozole on residual cancer cells as well as markers of mitochondrial and fatty acid metabolism. Herein we present the results of the molecular and clinical analyses. Methods: NAOMI is a phase II single-arm open-label study with use of letrozole for 4 to 12 weeks prior to surgical resection. Eligible patients were women over 18 years of age, post-menopausal, with stage I-III ER+, HER2- BC. Exclusion criteria included prior ET use or other neoadjuvant options. The primary objective was to assess whether residual cancer cells exhibit upregulation of the fatty acid transporter CPT1A compared to baseline. Secondary objectives included the proportion of subjects who had clinical response and whether residual cancer cells exhibit markers of altered mitochondrial and fatty acid metabolism compared to baseline tumors. Protocol was amended to include adherence rates to adjuvant AI. Results: A total of 77 women have consented to study participation since December 2022 including 57 evaluable patients. Molecular analyses were performed on diagnostic and post-letrozole tumor specimens from the first 33 patients. Immunohistochemistry was done using antibodies against Ki67, CPT1A, FASN, perilipin, CD36, and MT-CO2. CPT1A histoscore between baseline and post letrozole specimens were similar (paired t-test p=0.2636). Markers of altered mitochondrial and fatty acid metabolism including MT-CO2, CD36, FASN, Perilipin were unchanged when comparing pre and post-AI tissues. Post hoc comparisons of changes in Ki67 (marker of biological response to letrozole) vs. changes in metabolic markers were performed. Ki67+ cells were substantially decreased during neoadjuvant letrozole therapy (paired t-test p<0.0001). Linear regression analysis of residual tumor cell proliferation [post-letrozole log2(Ki67+1)] vs. letrozole-induced change in log2(MT-CO2) showed that tumors with more residual cell proliferation had greater levels of MT-CO2 (p=0.0278). Patients enrolled in NAOMI had a rate of adherence to adjuvant ET of 82%, higher than historical averages. Conclusions: NET is associated with a decrease in Ki67+ breast cancer cells however it has minimal impact on fatty acid and mitochondrial metabolism. It is suggested to increase adherence to adjuvant ET. Additional studies are planned to elucidate mechanisms of resistance in those samples that did not show a decrease in Ki67. Clinical trial information: NCT04568616 .

De-escalation of breast cancer surgery using vacuum-assisted biopsy (VAB): Interim results.

e12590 Background: Currently, there is a point of view according to which, in patients diagnosed with breast cancer (BC), surgical intervention when achieving a complete pathological response (pCR) after neoadjuvant systemic therapy (NST) is diagnostic, not therapeutic, and does not affect long-term treatment outcomes. Vacuum-assisted biopsy (VAB) of the tumor bed in breast cancer has shown promising results as a minimally invasive method for diagnosing pCR. This work presents a prospective analysis of treatment of patients with triple-negative and HER2-positive breast cancer who achieved pCR after NST and who underwent VAB alone without subsequent breast surgery. Methods: Women aged 18 years old and older with unicentric (cT1-2N0-1M0) triple-negative or HER2-positive breast cancer were included. Primary lesions were marked with a single clip before NST. In cases with nodal involvement (cN1) the affected lymph nodes were also clipped. Patients with TNBC received 4 cycles of AC q21d followed by 12 cycles of weekly paclitaxel and carboplatin AUC 2.0. HER2+ patients received dual anti-HER2 blockade with chemotherapy (TCHP or AC-DHP regimen). Breast US, mammography and mammolymphoscintigraphy were used at baseline and at response evaluation. Patients with complete clinical response after NST underwent VAB with 7G needle and US-guidance simultaneously with the sentinel lymph node biopsy and/or targeted axillary dissection. In case if no invasive or in situ residual tumor cells were detected (ypT0N0), no further breast surgery was performed and patients underwent subsequent radiation therapy. Primary endpoint was 2-year ipsilateral breast tumour recurrence-free survival [IBTR-FS]. Secondary endpoints included 2-year disease-free survival (DFS) and complication rates. The study is registered on сlinicaltrials.gov, NCT04293796. Results: 35 patients with a mean age of 48.3 (31–67) years were included in the trial. Examination of VAB samples showed that 11 (31.4%) patients had a residual tumor, and in 24 (68.6%) patients no tumor cells were detected (ypT0N0). This 24 patients were included in the analysis. Median follow-up was 26 months. Median survival was not reached for any endpoint. 2-year IBTR-FS was 91.7% in the VAB group. 2-year DFS was 83.3% in the VAB group. We registered 4 events: in 2 patients biopsy-proven de novo breast cancer occurred in contralateral breast, in 1 patient recurrence occurred in the postoperative zone and in 1 patient recurrence occurred in another quadrant of the ipsilateral breast. Conclusions: Additional observation and large randomized prospective studies are needed to determine the safety of VAB use. Clinical trial information: NCT04293796 .

Efficacy of GCN2 inhibition by a novel small molecule AP030 in acute leukemia.

6532 Background: GCN2 is an evolutionarily conserved kinase and a pivotal regulator of the Integrated Stress Response (ISR) that is activated in response to amino acid scarcity. Active GCN2 phosphorylates translation initiation factor eIF2α resulting in the attenuation of global protein synthesis. ISR signaling primarily promotes cell survival but may trigger cell death, dependent on the cellular context. In hematological tumors GCN2 promotes tumor cell survival under conditions of nutrient scarcity. Several GCN2 inhibitors are in clinical development for treatment of both solid and hematological tumors. Here, we describe the preclinical results of a novel, selective ATP-competitive inhibitor of GCN2. Methods: GCN2 inhibition by AP030 was determined using a biochemical Lanthascreen assay and a cell based HTRF assay measuring eIF2a phosphorylation following stimulation with Borrelidin. Kinase selectivity was determined using KinomeScan, and bespoke biochemical and cell-based assays. Interaction of AP030 with GCN2 was determined using X-ray crystallography. AP030 activity in disease-relevant tumor cell lines was determined using cell viability, caspase activation, protein expression and qPCR gene expression endpoints. Inhibition of hematological tumor growth and induction of cell death was investigated in patient samples, and ALL and AML in vivo animal models. Results: Potent inhibition of GCN2 in the Lanthascreen assay was demonstrated with AP030 (Ki of 4.4nM). Following stimulation with Borrelidin, AP030 inhibited eIF2a phosphorylation with an IC50 of 50.8nM and inhibited downstream targets CHAC1 and DDIT3 measured by qPCR. X-ray crystallography confirmed that AP030 binds to the ATP-binding site of GCN2. The KinomeScan confirmed that AP030 was highly selective against the human kinome. AP030 led to partial or complete reduction of AML cell line viability as a single agent and acted synergistically with asparaginase in ALL cell lines. Caspase 3/7 induction was observed in the AML and ALL cell lines evaluated and AP030 increased the proportion of cells undergoing apoptosis in AML patient primary samples. In the CCRF-CEM ALL systemic in vivo tumor model AP030 inhibited tumor growth in combination with asparaginase (TGI 79.33%). Treatment with 0.5-5mg/kg (q.d.) of AP030 resulted in dose-dependent tumor growth inhibition and regression of the MOLM-16 AML in vivo model (TGI 97.37% 5mg/kg). RNA sequencing of residual tumor cells revealed disruption of amino acid and protein metabolism, consistent with GCN2 inhibition. Conclusions: Targeting hematological tumor reliance on the GCN2 arm of the ISR during nutrient scarcity is a novel approach to preventing tumor cell survival. AP030 a novel, potent, selective, ATP-competitive kinase inhibitor has been shown to lead to impressive efficacy in acute leukemia. Based on these preclinical results, a phase 1/2 study has been initiated in AML.

Oridonin, a small molecule inhibitor of cancer stem cell with potent cytotoxicity and differentiation potential

Cancer stem cells (CSCs) drive malignant tumor progression, recurrence, and metastasis with unique characteristics, including self-renewal and resistance to conventional treatments. Conventional differentiation inducers, although promising, have limited cytotoxicity and may inadvertently enhance CSC stemness. To address these challenges, ongoing efforts are dedicated to developing strategies that can effectively combine both cytotoxicity and differentiation-inducing effects. In this study, we introduce oridonin (Ori), a small molecule with dual differentiation-inducing and cytotoxicity properties capable of eliminating tumor CSCs. We isolated CSCs in B16F10 cells using the Hoechst side population method and assessed the differentiation effect of Ori. Ori's differentiation-inducing effect was further evaluated using human acute promyelocytic leukemia. The cytotoxic potential of Ori against MCF-7 and B16F10 cell lines was assessed through various methods. In vivo anti-tumor and anti-CSC efficacy of Ori was investigated using mouse melanoma and CSCs melanoma models. Safety evaluation included zebrafish embryotoxicity and mouse acute toxicity experiments. As a result, Ori effectively dismantles tumorspheres, inhibits proliferation, and reduces the expression of CSC-specific markers. It induces significant differentiation, especially in the case of NB4. Additionally, Ori upregulates TP53 expression, mitigates the hypoxic tumor microenvironment, suppresses stemness, and inhibits PD-L1 expression, prompting a robust anti-cancer immune response. Ori demonstrates pronounced cytotoxicity, inducing notable pro-apoptotic effects on B16F10 and MCF-7 cells, with specific triggering of mitochondrial apoptosis. Importantly, Ori maintains a commendable biosafety record. The dual-action prowess of Ori not only induces the differentiation of CSCs but also dispatches differentiated and residual tumor cells, effectively thwarting the relentless march of tumor progression.

Biomimetic bone-periosteum scaffold for spatiotemporal regulated innervated bone regeneration and therapy of osteosarcoma

The complexity of repairing large segment defects and eradicating residual tumor cell puts the osteosarcoma clinical management challenging. Current biomaterial design often overlooks the crucial role of precisely regulating innervation in bone regeneration. Here, we develop a Germanium Selenium (GeSe) co-doped polylactic acid (PLA) nanofiber membrane-coated tricalcium phosphate bioceramic scaffold (TCP-PLA/GeSe) that mimics the bone-periosteum structure. This biomimetic scaffold offers a dual functionality, combining piezoelectric and photothermal conversion capabilities while remaining biodegradable. When subjected to ultrasound irradiation, the US-electric stimulation of TCP-PLA/GeSe enables spatiotemporal control of neurogenic differentiation. This feature supports early innervation during bone formation, promoting early neurogenic differentiation of Schwann cells (SCs) by increasing intracellular Ca2+ and subsequently activating the PI3K-Akt and Ras signaling pathways. The biomimetic scaffold also demonstrates exceptional osteogenic differentiation potential under ultrasound irradiation. In rabbit model of large segment bone defects, the TCP-PLA/GeSe demonstrates promoted osteogenesis and nerve fibre ingrowth. The combined attributes of high photothermal conversion capacity and the sustained release of anti-tumor selenium from the TCP-PLA/GeSe enable the synergistic eradication of osteosarcoma both in vitro and in vivo. This strategy provides new insights on designing advanced biomaterials of repairing large segment bone defect and osteosarcoma.

Metaplastic breast cancer with a unique presentation and complete response to chemotherapy: a case report

BackgroundMetaplastic breast carcinomas are a rare variant group of breast carcinomas. They are usually high-grade and triple-negative tumors. They often present with large primary tumor sizes. However, the involvement of axillary lymph nodes is infrequent at the time of diagnosis. Metaplastic breast carcinomas are associated with a worse prognosis and a poorer response to chemotherapy in comparison with other non-metaplastic triple-negative breast cancers. Up until this point, there are no specific treatment recommendations for metaplastic breast carcinomas beyond those intended for invasive breast cancer in general.Case presentationA 40-year-old woman complained of a palpable mass in her left axilla. On ultrasonography, the mass was solid, spindle-shaped, hypoechoic with regular borders, and exhibited decreased vascularity. At first, the mass appeared to be of a muscular origin. There was not any clinical nor ultrasonic evidence of a primary breast tumor. On magnetic resonance imaging, the axillary mass was a well-defined with regular borders, measuring 24 × 35 mm. Needle biopsy showed a spindle cell tumor with mild to moderate atypia. The subsequent surgical resection revealed a spindle cell neoplasm within a lymph node, favoring a metastatic origin of the tumor. The tumor cells lacked expression of estrogen, progesterone, and HER2 receptors. PET-CT scan indicated pathological uptake in the left breast. Accordingly, the patient was diagnosed with metaplastic breast cancer that had metastasized to the axillary lymph node. She commenced a combined chemotherapy regimen of doxorubicin and cyclophosphamide. After six treatment cycles, she underwent left modified radical mastectomy with axillary lymph node dissection. Pathological examination of the specimens revealed a total burn-out tumor in the breast due to excellent treatment response. There were no residual tumor cells. All dissected lymph nodes were free of tumor. At the one-year follow-up, the patient showed no signs of tumor recurrence.ConclusionThis report sheds light on a distinctive presentation of metaplastic breast carcinoma, emphasizing the need for vigilance in diagnosing this rare and aggressive breast cancer variant. In addition, the patient’s remarkable response to chemotherapy highlights potential treatment avenues for metaplastic breast cancer.

Correlation of microscopic tumor extension with tumor microenvironment in esophageal cancer patients

ObjectiveIn the era of image-guided adaptive radiotherapy, definition of the clinical target volume (CTV) is a challenge in various solid tumors, including esophageal cancer (EC). Many tumor microenvironmental factors, e.g., tumor cell proliferation or cancer stem cells, are hypothesized to be involved in microscopic tumor extension (MTE). Therefore, this study assessed the expression of FAK, ILK, CD44, HIF-1α, and Ki67 in EC patients after neoadjuvant radiochemotherapy followed by tumor resection (NRCHT+R) and correlated these markers with the MTE.MethodsFormalin-fixed paraffin-embedded tumor resection specimens of ten EC patients were analyzed using multiplex immunofluorescence staining. Since gold fiducial markers had been endoscopically implanted at the proximal and distal tumor borders prior to NRCHT+R, correlation of the markers with the MTE was feasible.ResultsIn tumor resection specimens of EC patients, the overall percentages of FAK+, CD44+, HIF-1α+, and Ki67+ cells were higher in tumor nests than in the tumor stroma, with the outcome for Ki67+ cells reaching statistical significance (p < 0.001). Conversely, expression of ILK+ cells was higher in tumor stroma, albeit not statistically significantly. In three patients, MTE beyond the fiducial markers was found, reaching up to 31 mm.ConclusionOur findings indicate that the overall expression of FAK, HIF-1α, Ki67, and CD44 was higher in tumor nests, whereas that of ILK was higher in tumor stroma. Differences in the TME between patients with residual tumor cells in the original CTV compared to those without were not found. Thus, there is insufficient evidence that the TME influences the required CTV margin on an individual patient basis.Trial registration number and dateBO-EK-148042017 and BO-EK-177042022 on 20.06.2022, DRKS00011886, https://drks.de/search/de/trial/DRKS00011886.

A Redox-Triggered Autophagy-Induced Nanoplatform with PD-L1 Inhibition for Enhancing Combined Chemo-Immunotherapy.

Epirubicin (EPI) alone can trigger mildly protective autophagy in residual tumor cells, resulting in an immunosuppressive microenvironment. This accelerates the recurrence of residual tumors and leads to antiprogrammed death ligand 1 (anti-PD-1)/PD-L1 therapy resistance, posing a significant clinical challenge in tumor immunotherapy. The combination of checkpoint inhibitors targeting the PD-1/PD-L1 pathway and amplifying autophagy presents an innovative approach to tumor treatment, which can prevent tumor immune escape and enhance therapeutic recognition. Herein, we aimed to synthesize a redox-triggered autophagy-induced nanoplatform with SA&EA-induced PD-L1 inhibition. The hyaluronic acid (HA) skeleton and arginine segment promoted active nanoplatform targeting, cell uptake, and penetration. The PLGLAG peptide was cleaved by overexpressing matrix metalloproteinase-2 (MMP-2) in the tumor microenvironment, and the PD-L1 inhibitor D-PPA was released to inhibit tumor immune escape. The intense autophagy inducers, STF-62247 and EPI, were released owing to the cleavage of disulfide bonds influenced by the high glutathione (GSH) concentration in tumor cells. The combination of EPI and STF induced apoptosis and autophagic cell death, effectively eliminating a majority of tumor cells. This indicated that the SA&EA nanoplatform has better therapeutic efficacy than the single STF@AHMPP and EPI@AHMPTP groups. This research provided a way to set up a redox-triggered autophagy-induced nanoplatform with PD-L1 inhibition to enhance chemo-immunotherapy.

Modified scoring system for the quantitative assessment of histological regression in peritoneal carcinomatosis after pressurized intraperitoneal aerosol chemotherapy: A pilot study.

Peritoneal carcinomatosis is one of the leading causes of death in patients with gastrointestinal cancer. Newer locoregional treatment concepts include pressurized intraperitoneal aerosol chemotherapy (PIPAC), the regional application of pressurized chemotherapeutic agents to the abdominal cavity, which is usually performed every 4 to 8 weeks. One of the main challenges of PIPAC therapy remains the objective assessment of treatment response. The present study describes a new scoring system to histologically assess the regression of peritoneal cancer following PIPAC therapy, quantitative assessment of histological regression in peritoneal carcinomatosis (QARP). Peritoneal biopsies from 27 patients with peritoneal metastases undergoing PIPAC were obtained and processed in a standardized fashion. Biopsies were scored according to the QARP grading system. The five-tiered system was graded as follows, Grade 0, no residual tumor cells with regressive changes present; grade 1, 1-25% viable tumor cells per tumor focus with regressive changes present; grade 2, 26-50% viable tumor cells per tumor focus with regressive changes present; grade 3, 51-75% viable tumor cells per tumor focus with few regressive changes; grade 4, >75% viable tumor cells per tumor focus with minimal or no regressive changes. Based on the new grading system, the study cohort was divided into QARP responders and QARP non-responders following PIPAC treatment. Higher QARP scores were significantly correlated with higher PCI scores (r=0.32; P=0.007). However, no difference in overall survival was detected between QARP responders and QARP non-responders. Further studies are required to ascertain the reproducibility and prognostic significance of QARP.

Abstract PO4-03-03: Conditional Use of Serial Serum Tumor Markers CA 15.3 and CEA as Predictors of Disease Relapse in Patients with High-Risk Early-Stage Breast Cancer

Abstract Background: Because of the diagnosis at an earlier stage, and the wider availability of more effective therapies, treatment outcomes of patients with breast cancer are getting much better resulting in an increasing proportion of patients surviving their disease, however, a significant percentage of patients with early-stage disease at initial diagnosis may eventually relapse. Residual tumor cells can remain dormant for many years before causing tumor recurrence. Physical examination and mammography are strongly recommended in surveillance guidelines, but data on routine blood tests or imaging is lacking. The revolution made in recent years, following the approval of novel targeted and immunotherapy agents, may have better outcome if started earlier in the disease course with the lowest tumor burden and in patients with good performance status and adequate organs’ function. Additionally, early detection of oligometastatic disease can give a chance for cure for a subset of these patients. Levels of CA15.3 and CEA are used in decision making in the metastatic setting but their role in surveillance is still controversial. We aim to investigate whether serial measurement of tumor markers, when it correlates with tumor bulk (conditional), can detect early asymptomatic recurrence among subset of patients with high-risk early-stage breast cancer. Methods: Patients with high-risk early-stage breast cancer were invited to participate. High-risk features include any of the following: large tumor size (T3/4), grade-3, node-positive, triple-negative, HER2-positive or hormone receptor (HR)-negative disease. Patients were considered eligible if they have elevated CA15.3 and/or CEA at baseline, that subsequently normalize 6 weeks after surgical resection; upfront or following neoadjuvant chemotherapy. Serial testing of the elevated CA15.3 and/or CEA is done every 2 months thereafter, samples are cryopreserved and will not be processed until disease relapse. As such results will not be used for clinical decisions. The study is still ongoing, we here present an interim analysis evaluating the correlation between certain tumor characteristics and elevated serum marker(s) levels. Results: Since the launch of the study, 367 patients deemed high-risk by the above criteria, accepted to participate. Abnormal baseline CA15.3 and/or CEA was found in 110 (30%); 65 (18%) patients had elevated CA 15.3 while elevated CEA was found in 45 (12%) patients. Abnormal CA 15.3 was found in 27% of cases with T3/4 disease compared with 13% in T1/2 disease (p=0.001), and in 21% of node positive disease versus 7% in node negative disease (p=0.002), in 9% of HR negative disease versus 20% in HR-positive (P=0.038). Tumor grade and HER2 status were not associated with significant difference. Regarding CEA, abnormal levels were detected in 24% of HER2-positive disease compared to 5% of HER2-negative disease (P&amp;lt; 0.0001). Other tumor features were not associated with significant difference. Conclusions: Only a third of patients with high-risk early-stage breast cancer had high level of serum tumor markers at initial diagnosis and thus such markers may correlate with tumor presence. Large tumors (T3/4) and node positive disease were associated with high CA15.3 but not CEA. HER2-stutus and tumor grade had no effect on CA15.3 level, while HER2 positive disease correlated well with high CEA. Citation Format: Sarah Edaily, Baha' Sharaf, Maher Sughayer, Lina Yousef, Hala Abu-Fares, Sarah Abdel-Razeq, Hala Abu-Jaish, Mahmoud Abunasser, Suhaib Khater, Anas Zayed, Osama El Khatib, Rahaf Rahal, Hazem Abdulelah, Maria Shraim, Hikmat Abdel-Razeq. Conditional Use of Serial Serum Tumor Markers CA 15.3 and CEA as Predictors of Disease Relapse in Patients with High-Risk Early-Stage Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-03-03.

Injectable hydrogel with doxorubicin-loaded ZIF-8 nanoparticles for tumor postoperative treatments and wound repair

The need for tumor postoperative treatments aimed at recurrence prevention and tissue regeneration have raised wide considerations in the context of the design and functionalization of implants. Herein, an injectable hydrogel system encapsulated with anti-tumor, anti-oxidant dual functional nanoparticles has been developed in order to prevent tumor relapse after surgery and promote wound repair. The utilization of biocompatible gelatin methacryloyl (GelMA) was geared towards localized therapeutic intervention. Zeolitic imidazolate framework-8@ceric oxide (ZIF-8@CeO2, ZC) nanoparticles (NPs) were purposefully devised for their proficiency as reactive oxygen species (ROS) scavengers. Furthermore, injectable GelMA hydrogels loaded with ZC NPs carrying doxorubicin (ZC-DOX@GEL) were tailored as multifunctional postoperative implants, ensuring the efficacious eradication of residual tumor cells and alleviation of oxidative stress. In vitro and in vivo experiments were conducted to substantiate the efficacy in cancer cell elimination and the prevention of tumor recurrence through the synergistic chemotherapy approach employed with ZC-DOX@GEL. The acceleration of tissue regeneration and in vitro ROS scavenging attributes of ZC@GEL were corroborated using rat models of wound healing. The results underscore the potential of the multifaceted hydrogels presented herein for their promising application in tumor postoperative treatments.

YY2/BUB3 Axis promotes SAC Hyperactivation and Inhibits Colorectal Cancer Progression via Regulating Chromosomal Instability.

Spindle assembly checkpoint (SAC) is a crucial safeguard mechanism of mitosis fidelity that ensures equal division of duplicated chromosomes to the two progeny cells. Impaired SAC can lead to chromosomal instability (CIN), a well-recognized hallmark of cancer that facilitates tumor progression; paradoxically, high CIN levels are associated with better therapeutic response and prognosis. However, the mechanism by which CIN determines tumor cell survival and therapeutic response remains poorly understood. Here, using a cross-omics approach, YY2 is identified as a mitotic regulator that promotes SAC activity by activating the transcription of budding uninhibited by benzimidazole 3 (BUB3), a component of SAC. While both conditions induce CIN, a defect in YY2/SAC activity enhances mitosis and tumor growth. Meanwhile, hyperactivation of SAC mediated by YY2/BUB3 triggers a delay in mitosis and suppresses growth. Furthermore, it is revealed that YY2/BUB3-mediated excessive CIN causes higher cell death rates and drug sensitivity, whereas residual tumor cells that survived DNA damage-based therapy have moderate CIN and increased drug resistance. These results provide insights into the role of SAC activity and CIN levels in influencing tumor cell survival and drug response, as well as suggest a novel anti-tumor therapeutic strategy that combines SAC activity modulators and DNA-damage agents.