Herein in the present study we reported genomic alterations in primary prostate cancer tissue and matched lymph node metastasis. In particular, KIT, HRAS and CTNNB1 were associated with worse overall survival disease free survival (p = 0.02) respect to unaltered group in cBioPortal.
In an interesting study by Zheng et al it has been investigated the role of 37 genes to predict lymph node invasion. The results of the RNA sequence in this study showed that 18 of 37 genes exhibited dysregulated expression between PCa and lymph node invasion samples, indicating that dysregulated expression levels of different genes played an important role in the LNI of PCa16.
A similar well-designed study aimed at identifying the genes associated with the involvement of lymph nodes metastasis in patients with PCa and among 376 genes investigated three genes, RALGPS1, ZBTB34, and GOLGA1, had a significant copy number alteration17.
Pudova et al performed a bioinformatic analysis of The Cancer Genome Atlas (TCGA) data and RNA-Seq profiling of a Russian patient cohort to reveal prognostic markers of locally advanced lymph node-negative prostate cancer. Authors found different genes that were associated with favorable and unfavorable prognosis based on the TCGA (B4GALNT4, PTK6, and CHAT) and Russian patient cohort data (AKR1C1 and AKR1C3). Furthermore, authors revealed such genes for the TMPRSS2-ERG prostate cancer molecular subtype (B4GALNT4, ASRGL1, MYBPC1, RGS11, SLC6A14, GALNT13, and ST6GALNAC1)18.
Similarly, Schmidt et al we analyzed laser micro-dissected primary PC foci (n = 23), adjacent normal prostate tissue samples (n = 23) and lymph node metastases (n = 9) from ten hormone-naive PC patients. Genes important for PC progression were identified using differential gene expression and clustering analysis and they reported a list of 20 transcripts (2 upregulated, 18 downregulated). The seeding model significantly predicted time to BCR independently of clinicopathological variables in uni- and multivariate Cox-regression analysis in TCGA (univariate: HR 2.39, P < 0.0001, multivariate: HR 2.01, P < 0.0001) 19.
Several studies have investigated the genomic characteristics of metastatic hormone-sensitive PCa (mHSPC). A recent systematic review by Van der Eecken et al was conducted on 11 studies that included 1682 mHSPC patients. A comparative analysis of gene alteration frequencies across disease states revealed a relative increase from localised to castration-resistant tumours, with noteworthy enrichment of CTNNB1 alterations in mHSPC (5%)20.
In fact, patients with PCa with alterations in canonical WNT pathway genes, which lead to β-catenin activation, are refractory to androgen receptor-targeted therapies, underlying that this genomic alteration may harbor a more aggressive cancer 21.
These results are confirmed by Isaacsson Velho that showed that the different types of Wnt- pathway mutations (inactivating APC or RNF43 mutations vs activating CTNNB1 mutations) were independently associated with higher hazard of PSA progression than Wnt wild type (aHR 2.58, p = 0.023). Despite a strong trend in the same direction, CTNNB1 mutations showed no statistically significant association with higher hazard of PSA progression (aHR 2.12, p = 0.072)22.
Generally, cancer has been linked to mutations in ERBB4 gene 23, which in this study was confirmed as a highly unstable gene. No information was found on the sequenced p.Q264* missense mutation in this gene, even if this has been already sequenced in a colon cancer cell line 24. Regarding CSF1R, as for the SNP rs386693509, no MAF is reported on Data Bank for this mutation, but it has been sequenced on 15 patients out of 17 in our cohort (88.2%). Even if present in literature, this mutation is very little discussed and with an unknow pathogenic impact 25. In the FGFR gene, rs17881656 is including in a retrospective study which test NGS of selected cancer-associated genes in resected prostate cancer 26, while rs149119664 is not reported in literature, even if classified as pathogenic (score by 0.97) by the FATHMM prediction.
As concerning the analysis of prostate cancer sample and matched lymph node metastasis reported in Table 2, we found mostly concordance between both samples, underlining that the identification of alterations in primary tumor is extremely important for cancer prognosis prediction.
The Cancer Genome Atlas (TCGA) showed that 13 genes were recurrently mutated in prostate cancer: deletions of SPOP, TP53, FOXA1, PTEN, MED12, and CDKN1B; additional clinically relevant genes were identified with lower frequencies, including BRAF, HRAS, AKT1, CTNNB1, and ATM 27.
Despite the confirmation of these interesting results, it is important to underline that it is not easy and reliable to perform such analysis in standard patients during clinical settings, since we have also to consider the dynamic of tumor and long follow-up to be fulfilled. In this context, liquid biopsies may overcome the limitations of intrapatient tumour heterogeneity and of tissue biopsies allowing for monitoring PCa disease 28,29.
Although there are no technology available to detect circulating tumor cells in all their phenotype and dynamic processes, however new platforms and further studies are ongoing to overcome all limitations 30. In this context, the analysis of common alterations that are matched with lymph node metastasis can be helpful for cancer prognosis and treatment.
Before concluding we would like to underline some limitations. Firstly, the discovery data was small since included 17 patients and 45 samples. Furthermore, we applied a standard cancer hotspot and we did not assess further alterations.
Before concluding we would like to underline some limitations. Firstly, the discovery data was small since included 17 patients and 45 samples. Furthermore, we applied a standard cancer hotspot and we did not assess further alterations.