BackgroundKisspeptin and its G protein-coupled receptor (GPR) 54 are essential for activation of the hypothalamo-pituitary-gonadal axis. In the rat, the kisspeptin neurons critical for gonadotropin secretion are located in the hypothalamic arcuate (ARC) and anteroventral periventricular (AVPV) nuclei. As the ARC is known to be the site of the gonadotropin-releasing hormone (GnRH) pulse generator we explored whether kisspeptin-GPR54 signalling in the ARC regulates GnRH pulses.Methodology/Principal FindingsWe examined the effects of kisspeptin-10 or a selective kisspeptin antagonist administration intra-ARC or intra-medial preoptic area (mPOA), (which includes the AVPV), on pulsatile luteinizing hormone (LH) secretion in the rat. Ovariectomized rats with subcutaneous 17β-estradiol capsules were chronically implanted with bilateral intra-ARC or intra-mPOA cannulae, or intra-cerebroventricular (icv) cannulae and intravenous catheters. Blood samples were collected every 5 min for 5–8 h for LH measurement. After 2 h of control blood sampling, kisspeptin-10 or kisspeptin antagonist was administered via pre-implanted cannulae. Intranuclear administration of kisspeptin-10 resulted in a dose-dependent increase in circulating levels of LH lasting approximately 1 h, before recovering to a normal pulsatile pattern of circulating LH. Both icv and intra-ARC administration of kisspeptin antagonist suppressed LH pulse frequency profoundly. However, intra-mPOA administration of kisspeptin antagonist did not affect pulsatile LH secretion.Conclusions/SignificanceThese data are the first to identify the arcuate nucleus as a key site for kisspeptin modulation of LH pulse frequency, supporting the notion that kisspeptin-GPR54 signalling in this region of the mediobasal hypothalamus is a critical neural component of the hypothalamic GnRH pulse generator.

Self-amputation, the extreme form of self-mutilation, is uncommon. The vast majority of cases are associated with psychosis, with a small number being assigned the controversial diagnosis of body identity integrity disorder. In this article, we report two cases of non-psychotic self-amputation and their similarities with a view to highlighting the risk factors and formulating an appropriate management plan.

446 Background: ICONIC evaluated 4+4 cycles of FLOT-A (2-weekly standard FLOT with 10mg/kg of the anti-PDL1 antibody avelumab) for perioperative treatment of early-stage OGA. We report R0 resection rates, pathologic complete response rates (pCR), pathologic tumour regression grades (TRG) according to Mandard classification and progression free survival (PFS) data in the modified intention to treat population (mITT), and translational analyses. Methods: ICONIC is a single-arm phase II trial of FLOT-A in patients (pts) with ≥cT2-4 or N+ OGA. The pCR rate in surgical specimens was the primary endpoint. Response evaluation according to Mandard, R0 rates and PFS were among secondary endpoints. PD-L1 expression was assessed according to the combined positive score (CPS) with the 22C3 pharmDx kit. Results: The trial closed early after the pCR rate was 15% (95% CI: 49%-83%) once 34 pts in the mITT population (defined as pts who had 1-4 cycles FLOT-A and surgery) as the pre-specified aim to demonstrate a pCR rate of 25% in 40 pts was unlikely to be met. Baseline characteristics of the mITT population were: median age 64y, 79% male, 79% OG junction, 6% oesophageal, 15% stomach, 65% poorly differentiated, 79% T3/4, 59% N+. 91% of pts received all 4 pre-operative cycles and 97% of pts achieved R0 resections. PDL1 CPS ≥1 and CPS ≥5 were nevertheless associated with increased TRG3 and decreased TRG4/5 rates. 3/34 pts (9%) had hypermutated/MMRd tumours and after their exclusion, the association of higher CPS with better TRG3 and decreased TRG4/5 remained. With a median follow up duration of 15.8 months the 12-month PFS was 93.1% (95% CI: 75.1%-98.2%) which is promising compared to historic results with peri-operative FLOT. Conclusions: Although FLOT-A failed to increase pCR rates to 25%, there is a trend towards higher TRG3 and lower TRG4/5 in pts with PDL1 CPS≥1 and CPS≥5 and promising PFS indicate activity of immunotherapy in combination with FLOT chemotherapy. Translational and biomarker analyses by exome- and RNA-sequencing, and multiplex immune cell staining are ongoing and will be reported. Clinical trial information: NCT03399071 . [Table: see text]

Background: The utility of molecular residual disease (MRD) detection by circulating tumor (ct)DNA in early-stage (pT2+ or N+, M0) esophagogastric adenocarcinoma treated with peri-operative systemic therapy has not been assessed in prospective trials. Methods: This exploratory analysis of the phase 2 ICONIC trial (NCT03399071), assessed whether ctDNA can predict recurrence and determine the efficacy of 4xFLOT+avelumab (FLOT-A) before and after surgery. Exome sequencing of pre-treatment biopsies was successful in 24/26 patients (pts) (92.3%) who had received FLOT-A and had undergone surgery at the time of analysis. All pts had R0 resections. Tumor-informed ctDNA assays (SignateraTM) were designed for these 24 pts and 220 serial plasma samples were analyzed. Pathologic response was assessed using Mandard tumor regression grading (TRG1 complete, 2 excellent, 3 good, 4 poor and 5 no response). The median follow-up was 17.0m from surgery. Progression free survival (PFS) was calculated from surgery to radiological recurrence or death. Results: ctDNA was detected in 23/24 pts (95.8%) prior to treatment. PFS was significantly shorter for pts with a mean number of tumor DNA molecules per ml plasma in the middle & highest tertile (p=0.049, HR=8.33, 95% CI: 1.01-1083, Firth Correction for Cox regression). 6 pts remained ctDNA-positive post neoadjuvant chemotherapy (NAC). None of these pts had a TRG1/2, 3 (50.0%) had TRG3 and 3 (50%) TRG4/5 in the resection specimen. Of 18 ctDNA-negative pts 5 (27.8%) had TRG1/2, 10 (55.6%) TRG3 and 3 (16.7%) TRG4/5. Post-surgery and prior to adjuvant therapy, 6/24 pts were ctDNA-positive. ctDNA positivity at this time point was associated with significantly shorter median PFS (12.9m) compared to ctDNA-negative status (PFS not reached, p<0.0001, HR=27, 95%CI: 3.0-241). Nodal status and Mandard TRG are routinely used as clinical predictors. Only the former was significantly associated with poor median PFS (pN+: 13.5m, pN-: not reached, p=0.027, HR=11, 95%CI: 1.3-98). Of 6 pts who remained ctDNA positive post-operatively, none achieved ctDNA clearance despite adjuvant FLOT-A. The median lead-time from ctDNA positivity after surgery to recurrence was 11.4 months. Conclusions: Post-NAC/pre-surgical ctDNA positivity correlated with worse pathological response. Persistent ctDNA after NAC & surgery was a stronger predictor of recurrence than nodal status or TRG in the resection specimen. Post-operative adjuvant therapy failed to clear ctDNA in any of the pts who were ctDNA positive after surgery, indicating that administering more of the same treatment is ineffective. This provides an opportunity to test new adjuvant therapies in pts who remain ctDNA positive after surgery. Whether post-operative therapy can be omitted in pts who are ctDNA negative after surgery should be assessed in future trials. Citation Format: Marco Gerlinger, Anderley Gordon, Louise J. Barber, Georgios Laliotis, Avani Athauda, Benjamin Challoner, Andrew Woolston, Sonia Mansukhani, Matt Dunstan, Nikoletta Petrou, Komel Khabra, Retchel Lazaro-Alcausi, Richard Crux, Victoria Borja, Ruwaida Begum, Isma Rana, Charuta Palsuledesai, Meenakshi Malhotra, Minetta Liu, Adham Jurdi, Shruti Sharma, Sheela Rao, Sacheen Kumar, David Cunningham, Ian Chau, Naureen Starling, M Asif Chaudry. Circulating tumor DNA for recurrence prediction and efficacy analysis in the ICONIC trial of peri-operative FLOT and avelumab (PD-L1) in localized esophago-gastric adenocarcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5591.