Early onset colorectal cancer (EOCRC), defined as colorectal cancers in patients aged less than 50 years, is becoming an increasingly common issue, globally. Since 1994, the incidence of this condition has been rising by 2% annually. Approximately one in five patients under 50 years of age diagnosed with colorectal cancer have an underlying genetic predisposition syndrome. The detection of cancer among the other 80% of patients poses a considerable task, as there is no family history to advocate for commencing early screening in this group. Patients with EOCRC have distinct social, spiritual, fertility, and financial needs from their older counterparts that need to be addressed. This review discusses the risk factors associated with the development of EOCRC and current best practice for the management of this disease.

Sea turtle populations are directly and indirectly under threat from a range of anthropogenic processes. Perhaps the most visibly apparent of these is the disfiguring tumor disease epizootic (animal epidemic) known as fibropapillomatosis. Fibropapillomatosis continues to spread geographically, with prevalence of the disease also growing at a number of affected sites globally. Environmental exposures seem key to inducing tumor development, possibly through weakening host immune systems to the point of enabling pathogen-induced tumor formation. However, we do not yet understand the precise molecular and mutational events driving fibropapillomatosis tumor formation and progression. Similarly, many open questions remain about the role of the herpesvirus (chelonid herpesvirus 5, ChHV5) associated with the disease as a potential co-trigger, and whether its occurrence within tumors is causative or opportunistic. Without improved understanding of the basic biology of this disease epizootic, treatment, containment and mitigation options are severely hampered.To address fundamental questions relating to the oncogenic signaling, mutational spectrum, viral load, viral transcriptional status (lytic or latent) and spread, we employed transcriptomic profiling, whole genome sequencing, immunohistochemistry and environmental (e)DNA-based monitoring of viral shedding. In particular we focused on the mutational landscape of tumors and assessing the transcriptional similarity of external (skin) and internal (visceral organs) tumors, and the oncogenic signaling events driving early stage tumor growth and post-surgical tumor regrowth. These analyses revealed that internal fibropapillomatosis tumors are molecularly distinct from the more common external tumors. However, our molecular analyses also revealed that there are a small number of conserved potentially therapeutically targetable molecular vulnerabilities in common between internal and external tumors, such as the MAPK, Wnt, TGFβ and TNF oncogenic signaling pathways. We also determined that the tumor genomes can harbor copy number gains, indicating potentially viral-independent oncogenic processes. Genes within such mutated genomic regions have known roles in human skin cancer, including MAPK-associated genes. Turtles attempt to mount an immune response, but in some animals this appears to be insufficient to prevent tumor development and growth. ChHV5 was transcriptionally latent in all tumor stages sequenced, including early stage and recurrent tumors. We also revealed that the tumors themselves are the primary source of viral shedding into the marine environment and, if they are surgically removed, the level of ChHV5 in the water column drops.Together, these results offer an improved understanding of fibropapillomatosis tumorigenesis and provide insights into the origins, therapeutic treatment, and appropriate quarantine responses for this wildlife epizootic. Furthermore, they provide insights into human pathogen-induced cancers, particularly mechanisms which are difficult to study in the human and terrestrial context, such as time-course quantification-based monitoring of viral shedding.

Kinase Suppressor of RAS 1 (KSR1) is a scaffolding protein for the RAS-RAF-MEK-ERK pathway, which is one of the most frequently altered pathways in human cancers. Previous results have shown that KSR1 has a critical role in mutant RAS-mediated transformation. Here, we examined the role of KSR1 in mutant BRAF transformation. We used CRISPR/Cas9 to knock out KSR1 in a BRAFV600E-transformed melanoma cell line. KSR1 loss produced a complex phenotype characterised by impaired proliferation, cell cycle defects, decreased transformation, decreased invasive migration, increased cellular senescence, and increased apoptosis. To decipher this phenotype, we used a combination of proteomic ERK substrate profiling, global protein expression profiling, and biochemical validation assays. The results suggest that KSR1 directs ERK to phosphorylate substrates that have a critical role in ensuring cell survival. The results further indicate that KSR1 loss induces the activation of p38 Mitogen-Activated Protein Kinase (MAPK) and subsequent cell cycle aberrations and senescence. In summary, KSR1 function plays a key role in oncogenic BRAF transformation.

Alternative mRNA splicing is common in cancers. In BRAF V600E-mutated malignant melanoma, a frequent mechanism of acquired resistance to BRAF inhibitors involves alternative splicing (AS) of BRAF. The resulting shortened BRAF protein constitutively dimerizes and conveys drug resistance. Here, we have analysed AS in SK-MEL-239 melanoma cells and a BRAF inhibitor (vemurafenib)-resistant derivative that expresses an AS, shortened BRAF V600E transcript. Transcriptome analysis showed differential expression of spliceosome components between the two cell lines. As there is no consensus approach to analysing AS events, we used and compared four common AS softwares based on different principles, DEXSeq, rMATS, ASpli, and LeafCutter. Two of them correctly identified the BRAF V600E AS in the vemurafenib-resistant cells. Only 12 AS events were identified by all four softwares. Testing the AS predictions experimentally showed that these overlapping predictions are highly accurate. Interestingly, they identified AS caused alterations in the expression of melanin synthesis and cell migration genes in the vemurafenib-resistant cells. This analysis shows that combining different AS analysis approaches produces reliable results and meaningful, biologically testable hypotheses.

Although a rare disease, neuroblastoma accounts for the highest proportion of childhood cancer deaths. There is a lack of recurrent somatic mutations in neuroblastoma embryonal tumours, suggesting a possible role for epigenetic alterations in driving this cancer. While an increasing number of reports suggest an association of MYCN with epigenetic machinery, the mechanisms of these interactions are poorly understood in the neuroblastoma setting. Utilising chemo-genomic approaches we revealed global MYCN-epigenetic interactions and identified numerous epigenetic proteins as MYCN targets. The epigenetic regulators HDAC2, CBX8 and CBP (CREBBP) were all MYCN target genes and also putative MYCN interactors. MYCN-related epigenetic genes included SMARCs, HDACs, SMYDs, BRDs and CREBBP. Expression levels of the majority of MYCN-related epigenetic genes showed predictive ability for neuroblastoma patient outcome. Furthermore, a compound library screen targeting epigenetic proteins revealed broad susceptibility of neuroblastoma cells to all classes of epigenetic regulators, belonging to families of bromodomains, HDACs, HATs, histone methyltransferases, DNA methyltransferases and lysin demethylases. Ninety-six percent of the compounds reduced MYCN-amplified neuroblastoma cell viability. We show that the C646 (CBP-bromodomain targeting compound) exhibits switch-like temporal and dose response behaviour and is effective at reducing neuroblastoma viability. Responsiveness correlates with MYCN expression, with MYCN-amplified cells being more susceptible to C646 treatment. Thus, exploiting the broad vulnerability of neuroblastoma cells to epigenetic targeting compounds represents an exciting strategy in neuroblastoma treatment, particularly for high-risk MYCN-amplified tumours.

Alternative mRNA splicing is common in cancers. In BRAF V600E mutated malignant melanoma a frequent mechanism of acquired resistance to BRAF inhibitors involves alternative splicing (AS) of BRAF. The resulting shortened BRAF protein constitutively dimerizes and conveys drug resistance. Here, we have analysed AS in SKMEL-239 melanoma cells and a BRAF inhibitor (vemurafenib) resistant derivative that expresses an AS, shortened BRAF V600E transcript. Transcriptome analysis showed differential expression of spliceosome components between the two cell lines. As there is no consensus approach to analysing AS events, we used and compared four common AS softwares based on different principles, DEXSeq, rMATS, ASpli, and LeafCutter. Two of them correctly identified the BRAF V600E AS in the vemurafenib resistant cells. Only 12 AS events were identified by all four softwares. Testing the AS predictions experimentally showed that these overlapping predictions are highly accurate. Interestingly, they identified AS caused alterations in the expression of melanin synthesis and cell migration genes in the vemurafenib resistant cells. This analysis shows that combining different AS analysis approaches produce reliable results and meaningful, biologically testable hypotheses.