In Situ Clonal Heterogeneity in Prostatic Diagnostic Biopsies

This is a retrospective, proof of concept study, which aims at reconstructing the cellular heterogeneity of the tumor in multi-needle diagnostic prostate biopsy as well as any biopsy containing potentially pre-malignant tissue, to study its implications in the clinical history of the disease. For each patient, 2 or more samples will be prepared starting from the FFPE diagnostic material. The biopsy used for assigning the Gleason score will be sequenced, together with two or more of the local peri-proximal biopsies with a higher level of differentiation. Samples will undergo Whole Exome Sequencing with an average coverage of 300x at the Wellcome Sanger Institute (WSI, Hinxton, UK). Sequencing data will be analysed for single nucleotide variants, copy number variants and structural variants by using state-of-the-art data analysis pipeline at WSI. 1. Reconstruction of local PCa heterogeneity in multi-needle diagnostic biopsy with different Gleason scores (6-10) using high-coverage whole exome sequencing (WES) and DP-based clonal analysis; 2. Characterization of the relationships between pathological differentiation (Gleason score) and genomics-measured heterogeneity and malignancy features; 3. Assessment of clinical implications of clonal heterogeneity. The study will include an average of 150 prostatic diagnostic biopsies from a cohort of 20 early metastatic PC patients and 20 non-relapsing/non-metastatic patients with indolent malignant disease.

Sex

Male

The inclusion criteria for the subjects in the indolent cohort will be:

* a local disease with Gleason ≤ 7 (3+4, i.e. more differentiated tissue is found in diagnostic biopsies, better overall prognosis)
* no metastasis whatsoever during the follow-up;

The inclusion criteria in the early-metastatic aggressive cohort will be:

* an advanced prostatic neoplasia with Gleason score ≥ 7 (4+3, i.e. less differentiated tissue is found in diagnostic biopsies, worse overall prognosis)
* multiple synchronous or metachronous metastasis.

Exclusion Criteria:

* insufficient material on the tissue biopsy to be left in archives for further evaluations/analyses;
* insufficient amount of tumor cells at baseline;

• BACKGROUNDAltmann A, Weber P, Bader D, Preuss M, Binder EB, Muller-Myhsok B. A beginners guide to SNP calling from high-throughput DNA-sequencing data. Hum Genet. 2012 Oct;131(10):1541-54. doi: 10.1007/s00439-012-1213-z. Epub 2012 Aug 11. PMID 22886560
• BACKGROUNDBeltran H, Prandi D, Mosquera JM, Benelli M, Puca L, Cyrta J, Marotz C, Giannopoulou E, Chakravarthi BV, Varambally S, Tomlins SA, Nanus DM, Tagawa ST, Van Allen EM, Elemento O, Sboner A, Garraway LA, Rubin MA, Demichelis F. Divergent clonal evolution of castration-resistant neuroendocrine prostate cancer. Nat Med. 2016 Mar;22(3):298-305. doi: 10.1038/nm.4045. Epub 2016 Feb 8. PMID 26855148
• BACKGROUNDBolger AM, Lohse M, Usadel B. Trimmomatic: a flexible trimmer for Illumina sequence data. Bioinformatics. 2014 Aug 1;30(15):2114-20. doi: 10.1093/bioinformatics/btu170. Epub 2014 Apr 1. PMID 24695404
• BACKGROUNDBolli N, Avet-Loiseau H, Wedge DC, Van Loo P, Alexandrov LB, Martincorena I, Dawson KJ, Iorio F, Nik-Zainal S, Bignell GR, Hinton JW, Li Y, Tubio JM, McLaren S, O' Meara S, Butler AP, Teague JW, Mudie L, Anderson E, Rashid N, Tai YT, Shammas MA, Sperling AS, Fulciniti M, Richardson PG, Parmigiani G, Magrangeas F, Minvielle S, Moreau P, Attal M, Facon T, Futreal PA, Anderson KC, Campbell PJ, Munshi NC. Heterogeneity of genomic evolution and mutational profiles in multiple myeloma. Nat Commun. 2014;5:2997. doi: 10.1038/ncomms3997. PMID 24429703
• BACKGROUNDChen X, Schulz-Trieglaff O, Shaw R, Barnes B, Schlesinger F, Kallberg M, Cox AJ, Kruglyak S, Saunders CT. Manta: rapid detection of structural variants and indels for germline and cancer sequencing applications. Bioinformatics. 2016 Apr 15;32(8):1220-2. doi: 10.1093/bioinformatics/btv710. Epub 2015 Dec 8. PMID 26647377
• BACKGROUNDCibulskis K, Lawrence MS, Carter SL, Sivachenko A, Jaffe D, Sougnez C, Gabriel S, Meyerson M, Lander ES, Getz G. Sensitive detection of somatic point mutations in impure and heterogeneous cancer samples. Nat Biotechnol. 2013 Mar;31(3):213-9. doi: 10.1038/nbt.2514. Epub 2013 Feb 10.