Cloning of Primary Human Tumors in Capillary Tube versus Petri Dish: A Head-to-Head Comparison

Abstract

Plating efficiencies (PEs) of primary human tumors cloned in a capillary assay system were compared to those derived from the conventional two-layer agar Petri dish assay system. A total of 143 consecutively received primary human tumors of 24 different pathologies were simultaneously tested in both assay systems. The successful clonal growth rate in the capillary assay was 82.7%, while in the Petri dish it was 64.7% (p less than 0.001). The median PE was 0.017% in the capillary assay demonstrating a 4.25-fold increase over the 0.004% PE of the Petri dish system. The data confirmed previous results showing that cancer cells of ovarian, breast, and lung origins clone with higher PE in capillary tubes. In contrast, we confirmed that stomach carcinoma cells were the only tumor type that showed a higher PE with the Petri dish method. In addition, this study shows for the first time that lymphomas and renal cell carcinoma, when they survive in vitro, clone equally well in both methods. However, the capillary cloning method resulted in a 66% success rate for lymphoma cell cloning, but Petri dish cloning resulted in only a 33% success rate. Thus, for some types of cancers (i.e., lymphoma), capillary cloning may be advantageous because it improves the probability of obtaining evaluable results. In other cases, the advantage of capillary cloning may be only the decreased amount of specimen and reagents needed for the assay.