Abstract 5500: Patient-derived organotypic cultures (PDOCs) from melanoma metastases as a precision medicine test to improve patient management

INTRODUCTION Despite significant improvements in advanced melanoma therapy, there is still a pressing need for innovative therapies. Here, we optimized a method for testing the drug sensitivity of PDOCs and evaluated whether this preclinical model could be a valid tool for rapidly determining the patient’s tumor response profile to approved and alternative therapies.

METHODS PDOCs were generated from melanoma metastases (> 60 specimens) after mechanical or enzymatic dissociation. Tissue fragments (<70um) were harvested, embedded in 3D collagen beads (1.5 mg/mL type I collagen), and cultured in a 96-well plate for 6 days, maintaining tumor and stromal viability. More than 20 primary cell lines from the same samples were also stabilized. The melanoma cells or the PDOCs were left untreated or treated with the patient’s own therapy or with alternative drugs, and the efficacy of treatments was evaluated by MTT assay and flow cytometry. CD8+ T cell infiltration and cytokine secretion were also investigated.

RESULTS The first experiments were set up to validate PDOCs as predictive preclinical models of patient response to therapy. We tested approved melanoma therapies (i.e., the combination of BRAF and MEK inhibitors, or anti-PD-1 antibodies) on the same melanoma specimens at the IDI and IEO institutes. More than 10 different samples were compared, finding reproducible results between the two Institutions. Furthermore, drug response in PDOCs was comparable to the clinical response of matched patients undergoing the tested therapy, demonstrating PDOCs are reliable predictive tools. Then, we used primary cell lines to screen a pool of ten different targeted agents selected through functional screening of a bioactive library of 512 compounds on patient-derived xenografts, and based on known drug resistance mechanisms in melanoma. The three best-performing compounds were subsequently studied in PDOCs as single agents or in combination with immunotherapy. We found high heterogeneity of drug efficacy in different melanoma samples with no obvious correlation to BRAF or NRAS mutations, metastasis type, or patients’ prior therapies. Of note, in some cases, the combination with an anti-PD-1 inhibitor significantly improved the efficacy of one or more of the three drugs.

CONCLUSIONS We optimized and validated PDOCs as personalized preclinical models suitable for assessing the drug sensitivity/resistance profile of individual patient-derived melanomas. By retaining tumor stromal components and heterogeneity, PDOCs could be used to predict patients’ clinical response to currently approved agents, helping oncologists expedite decision-making when several treatment options are possible. Furthermore, the model could be used to evaluate the effectiveness of alternative treatments on tumors resistant to approved therapies, and to explore new drug combinations.

Citation Format: Antonella Bresin, Fiorenza Lotti, Lauretta Levati, Pier F. Ferrucci, Francesca Ricci, Francesco Scicchitano, Zorika C. Di Rocco, Giandomenico Russo, Luisa Lanfrancone. Patient-derived organotypic cultures (PDOCs) from melanoma metastases as a precision medicine test to improve patient management. [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 5500.

Possible role of microbiome in the pathogenesis of endometriosis

INTRODUCTION

There is an urgent necessity to explore the complex pathophysiological nature of endometriosis, which may enable the rationale for new diagnostic and therapeutic strategies to be discovered. This systematic review aimed to clarify the bidirectional relationship between endometriosis and the microbiome and evaluate if the microbiome may be involved in endometriosis's pathogenesis, establishing a potential connection between the different studies.

EVIDENCE ACQUISITION

Studies were identified through a systematic literature search of papers that evaluated the microbiomes of human or other animal species with endometriosis and of those without in the electronic database PubMed/Medline, and Embase without a date restriction. We included all cohort studies focusing on the interaction between endometriosis and the microbiomes of humans or other mammals, evaluating if the microbiome may be involved in endometriosis's pathogenesis.

EVIDENCE SYNTHESIS

Endometriosis appears to be associated with elevated levels of different microorganisms across various microbiome sites. An ineffective immune response seems to play a key role in endometriosis pathogenesis, and there is some scientific proof to state that the immune response may be modulated by the microbiome. Interestingly, nine studies of our review detected species belonging to the phyla Proteobacteria, Bacteroidetes, and Negativicutes characterized by Gram-negative staining, that were significantly increased in endometriosis cohorts.

CONCLUSIONS

Laboratory and clinical investigations indicate that hosts' microbiome profiles with and without endometriosis can be significantly different. To further our understanding of the relationships between endometriosis and the host microbiome, more studies are necessary.

Male breast cancer: 6-year experience

AIM

Breast cancer in men is a very rare neoplasm accounting 1% of all breast cancer with an incidence ratio of 1:100 of men to women and about 1% of all malignancies in men. On the basis of the literature review the authors tried to determine the main characteristics of this rare neoplasm in terms of epidemiology, diagnosis, prognosis, treatment and survival.

METHODS

The authors report the experience of the Breast Unit of the San Giovanni Addolorata Hospital in Rome, where 4 cases of male breast cancer were observed and treated over 784 breast cancers.

RESULTS

All tumours were ductal carcinomas. The extent of disease was as follows: 3 cases with stage I and 1 case with Stage IIIB; in two cases estrogen and progesterone receptors expression was 100% and in the other two cases it was 20-80%. Median follow up was 57.5 months. At present, after 6-year follow up the three patients with stage I are in good conditions; the patient with stage III died after 27 months with metastatic disease.

CONCLUSIONS

Surgical treatment remains the gold standard in male breast cancer. The prognosis for males with breast cancer is similar to female patients on equal terms of stage of disease. Adjuvant therapy is based on retrospective studies of male breast cancer conducted over the past 20 years using the guidelines for breast cancer in women.

Retroperitoneal mesenchymal chondrosarcoma mimicking a large retroperitoneal sacral schwannoma

We report a case of retroperitoneal chondrosarcoma in which preoperative radiological study induced to a possible diagnosis of sacral schwannoma. A 25-year-old woman was admitted to our neurosurgical institute for a progressive sciatic pain with gait difficulties with a sudden radicular deficit with right positive Lasegue's sign at 30 degrees, loss of Achilles reflex, sensory deficit on right S1 dermatome, and complete motor deficit of right plantar flexion. We performed an en bloc removal of the lesion via an anterior retroperitoneal approach. We believe that the treatment of choice is radical surgical excision of the tumor with complete en-bloc removal of the lesion; postoperative radiotherapy and chemotherapy should be valuated case by case.

[The actual role of bilateral neck exploration in the treatment of primary hyperparathyroidism]

Surgery is the only curative treatment for primary hyperparathyroidism (pHPT). Surgical exploration is recommended for all patients with biochemically documented pHPT and signs or symptoms of the disease. Some patients are asymptomatic, others have subtle symptoms that disappear after parathyroid surgery. Felix Mandl successfully performed the first parathyroidectomy in 1925, using a bilateral neck exploration (BNE) with examination of all four glands and this remained the procedure of choice for pHPT into the 1990s. As over 80% of pHPT cases are due to a single parathyroid adenoma, many authors have questioned the need of BNE and have proposed directed unilateral approaches, termed "mini-invasive parathyroidectomies". The aim of this report is to define which is the actual role of the conventional surgical approach to pHPT.

[Intraoperative quick parathyroid hormone assay in thyroid surgery: preliminary experience on 36 cases]

Through the analysis of our preliminary experience on 36 consecutive cases of thyroid surgery, we assessed the feasibility of the rapid intraoperative assay of the intact parathyroid hormone (iPTH) as predictive risk factor of hypocalcemia versus seric calcium level on the first post-operative day to select the patients eligible to an early discharge. Furthermore, we managed to determine if iPTH level during thyroid surgery could point out the cases in which parathyroid autotransplantation is necessary, as the macroscopic evaluation of the parathyroid gland's viability is inadequate.

[Renal giant angiomyolipoma in tuberous sclerosis complex: case report and literature review]

The aim of this paper is to describe a typical clinical case of tuberous sclerosis complex (Bourneville disease) and discuss controversial issues about the management of this rare condition, with a short revision of the literature. Particularly, we define which is the role of the surgeon in the treatment of this very rare condition, that should be primary approached conservatively.

[The Bochdalek hernia in the adult: case report and review of the literature]

The Bochdalek hernia, the most common diaphragmatic hernia, except the hiatus hernia, is located on the posterolateral side of this muscle. This pathology is generally diagnosed in children; in fact only 105 such cases occurring in adults have been described in the literature. In these cases, surgical intervention is made necessary by the severity of potential complications. The Author's attention was drawn to a woman of 60 years of age, affected by pituitary nanism, who suffered from a left hand Bochdalek hernia. The symptomatology, characterised by abdominal pains and constipation had been presented for about one year. The computerised tomography confirmed the hernia of abdominal viscera in the thorax cavity. The intervention was conduced via the abdomen: the hernia were reduced, the hernial hole were closed with a double strata and the muscular plane reinforced with a synthetic prosthesis (dual mesh). The postoperative process was regular and the patient dismissed on 11th postoperative day.

[Benign cicatricial stenosis of colorectal anastomosis: considerations on 2 cases]

During the surgical treatment of two patients with benign anastomotic colorectal stenosis, the Authors registered the presence of concomitant tenacious adherence of the anastomotic line to the sacral bone. Such event, according to the Authors, could represent one of the causes of failure and greater risk of perforation during the treatment with the different endoscopic therapies that, nevertheless, ought to be considered the gold standard in the therapy of benign structures. The Authors developed their hypothesis physiopathologic on the basis of personal experience and of the search a diagnostic procedure able to highlight the presence of a tenacious adherence with solid structures during the operative evaluation. If further studies focused on this subject will bring to satisfactory results, this would represent a further aid for the evaluation of the best therapeutic approach of the benign post anastomotic stenosis.

[Abdominal approach to the treatment of the vestigial retrorectal tumors: our experience]

Although the vestigial retrorectal cysts are still rare, the number of the observed ones is destined to increase, as methods by imaging become routinely used in the clinical practice. Once diagnosed, the removal of retrorectal lesions should be mandatory. Therefore, by reporting three clinical cases, the Authors propose notes of technique above the abdominal approach used for the surgical treatment of these retrorectal congenital neoformations. In their experience, the anterior route had no postoperative complications, short stay, no neurological consequences and good long-term results.