Three dimensional organotypic ex vivo culture of tissues from post-operated tumor samples: Strengths and limitations.

e23151 Background: Evolution of tumor occurs in two phases, pretreatment phase, and posttreatment phase.Tumorigenic history and path of tumorigenic evolution determine the response of tumor cells to antitumor drug and thus the outcome of treatment. Carcinomas from the same organ-site with similar genomic alterations in different patients may vary in their tumorigenic history and their diverse paths of tumorigenic evolution which cause them respond differently to the same antitumor drugs. Uniqueness of tumorigenic history and paths of tumorigenic evolution in individual patient makes it ideal to test drugs, N-of-1. Here we present our experience with 3D organotypic ex vivo culture of tumor tissue from post-operated tumor samples. Methods: Informed consent was obtained from patients ( NCT02470715). The investigation was approved by IRB of the Avera Cancer Institute and the Western IRB. Surgically resected tissue was obtained from patients with different tumors of different organ sites including ovarian, breast, lung, endometrium, and cervix at the Avera Cancer Institute, SF, SD. Tissues from patients were collected in two formats, paired samples (tumor and tumor-adjacent normal) and unpaired samples. Results: As extracellular matrix lost in cell cultures, provide important signals for cell survival, differentiation and drug resistance we have established a protocol to culture slices in the 3D format. We have established 3D slice cultures (3x3 mm) of tumor-derived tissues which can be maintained ex vivo for at least three days. Tumor cells / normal cells from different tumors/tumor-adjacent normal tissues from day zero (non-cultured) were used to compare day1, day2, and day3 cultures. At the end of the culture period, slices were embedded in paraffin for histological analysis following H&E staining as well as IHC-staining for proliferation index (Ki-67), cellular proliferation signals (pS6RP), apoptosis (activated caspase 3), or tumor angiogenesis (CD31). Ki67 staining was characteristically different in cultured normal and cultured tumor tissues. Conclusions: Here, we show that tumor-derived tissues survive in 3D Matrigel culture for a minimum of 6 hours and maximum up to 3 days. Clinical trial information: NCT02470715.