Jana Šmardová

Single cell analysis revealed a coexistence of NOTCH1 and TP53 mutations within the same cancer cells in chronic lymphocytic leukaemia patients.

The clinical course in chronic lymphocytic leukaemia (CLL)npatients is diverse, reflecting the heterogeneous biologicalnbackground of this disease (Guix01eze & Wu, 2015). Among reportedndefects, mutations in NOTCH1 and TP53 genes represent potentnCLL progression drivers and contribute to diseasenchemo-refractoriness (Fabbri et al, 2011; Malcikova et al,n2015). Although parallel occurrence of NOTCH1 mutations andnTP53 defects has been noted in CLL patients (Weissmann et al,n2013; Stilgenbauer et al, 2014), the clonal composition ofnthese coexisting aberrations has not been yet studied. Tonclarify this phenomenon, we examined CLL patients withnconcurrently detected hotspot NOTCH1 and TP53 mutations usingnsingle cell analysis.

Detection and Functional Analysis of TP53 Mutations in CLL

Chronic lymphocytic leukemia (CLL) represents a prototype disease in which TP53 gene defects lead to inferior prognosis. Here, we present two distinct methodologies which can be used to identify TP53 mutations in CLL patients; both protocols are primarily intended for research purposes. The functional analysis of separated alleles in yeast (FASAY) can be flexibly adapted to a variable number of samples and provides an immediate functional readout of identified mutations. Amplicon-based next-generation sequencing then allows for a high throughput and accurately detects subclonal TP53 variants (sensitivity <1% of mutated cells).

Two Approaches to Cancer Development

BACKGROUNDnThe somatic mutation theory explaining the process of carcinogenesis is generally accepted. The theory postulates that carcinogenesis begins in a first renegade cell that undergoes gradual transformation from a healthy to a fully malignant state through the accumulation of genetic and epigenetic hits. This theory focuses specifically on mutations and genetic aberrations, and their impact on cells. It considers tumors as populations of sick cells that lose control of their own proliferation. The theory was put forward by Robert Weinberg and Douglas Hanahan, and is the predominant view in current cancer biology. By contrast, the tissue organization field theory proposed by Carlos Sonnenschein and Ana Soto considers loss of physiological structure and function by a tissue as key events in tumor development. According to this theory, tumors arise at a tissue rather than at a cellular level. It is based on a presumption that proliferation status, rather than quiescence, is the default position of cells in multicellular organisms.nnnAIMnThe article aims to provide answers to following questions: Are the views of proponents of the somatic mutation theory (the reductionists) and proponents of the tissue organization field theory (the organicists) incompatible and incommensurable, even when the mainstream of tumor biology has shifted its attention from tumor cells toward the tumor microenvironment? Where to find a third interconnecting systemic approach? Is it useful to be aware of the controversy between reductionists and organicists? What this awareness contributes to? How do these alternative views influence practical oncology and tumor biology in general?nnnCONCLUSIONnWhether the true position is held by reductionists or organicists is unimportant. What is important is to be aware of the existence of these two concepts because this knowledge makes the way we think about tumor origin and development, and how we set up and interpret our experiments, more precise.nnnKEY WORDSncarcinogenesis - mutation - cell - tissues - cell proliferation - cell quiescenceThis study was supported by grant of Internal Grant Agency of the Czech ministry of Health No. NT/13784-4/2012.The authors declare they have no potential conflicts of interest concerning drugs, products, oru202fservices used in the study.The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 29. 7. 2015Accepted: 27. 4. 2016.