Clinical significance of frequent somatic mutations detected by high-throughput targeted sequencing in archived colorectal cancer samples.

BACKGROUND: Colorectal cancer (CRC) is a heterogeneous disease with different molecular characteristics associated with many variables such as the sites from which the tumors originate or the presence or absence of chromosomal instability. Identification of such variables, particularly mutational hotspots, often carries a significant diagnostic and/or prognostic value that could ultimately affect the therapeutic outcome. METHODS: High-throughput mutational analysis of 99 CRC formalin-fixed and paraffin-embedded (FFPE) cases was performed using the Cancer Hotspots Panel (CHP) v2 on the Ion Torrent™ platform. Correlation with survival and other Clinicopathological parameters was performed using Fisher's exact test and Kaplan-Meier curve analysis. RESULTS: Targeted sequencing lead to the identification of frequent mutations in TP53 (65 %), APC (36 %), KRAS (35 %), PIK3CA (19 %), PTEN (13 %), EGFR (11 %), SMAD4 (11 %), and FBXW7 (7 %). Other genes harbored mutations at lower frequency. EGFR mutations were relatively frequent and significantly associated with young age of onset (p = 0.028). Additionally, EGFR or PIK3CA mutations were a marker for poor disease-specific survival in our cohort (p = 0.009 and p = 0.032, respectively). Interestingly, KRAS or PIK3CA mutations were significantly associated with poor disease-specific survival in cases with wild-type TP53 (p = 0.001 and p = 0.02, respectively). CONCLUSIONS: Frequent EGFR mutations in this cohort as well as the differential prognostic potential of KRAS and PIK3CA in the presence or absence of detectable TP53 mutations may serve as novel prognostic tools for CRC in patients from the Kingdom of Saudi Arabia. Such findings could help in the clinical decision-making regarding therapeutic intervention for individual patients and provide better diagnosis or prognosis in this locality.

Worst pattern of invasion and other histopathological features in oral cancer as determinants of prognosis and survival rate: A retrospective cohort analysis.

Oral cavity squamous cell carcinoma (OCSCC) is a well-recognized malignancy of the head and neck. Studies on patients with early-stage oral cancer have shown that they develop locally recurring and/or regional lymph node metastasis, which results in disease-associated mortality. Thus, early-stage oral cancer does not always present good prognoses. The present study aimed to determine the efficacy of using worst pattern of invasion (WPOI) and other histopathological features, such as prognostic factors in OCSCC, and analyze the impact of resection margin status and histopathological prognostic indicators on local recurrence (LR) and overall survival (OS) in patients with OCSCC. A retrospective cohort study was conducted by reviewing the charts of 63 patients with OCSCC treated with primary surgery at King Abdulaziz University Hospital between 2012 and 2019. An author and an experienced pathologist reviewed pathology slides. Associations of histopathological factors, including differentiation, stage, lymphovascular invasion, extracapsular extension, perineural invasion (PNI), WPOI and surgical margins, with LR or disease-free survival (DFS) were evaluated. Univariate analysis identified WPOI and PNI, and multivariate analysis identified the WPOI as predictive factors for LR and DFS. Kaplan-Meier analysis identified the WPOI and PNI as predictive factors for OS and WPOI as a predictive factor for DFS. Therefore, it may be concluded that WPOI and PNI are significant independent prognostic factors for local tumor control and DFS in patients with OCSCC.

Molecular characterisation in tongue squamous cell carcinoma reveals key variants potentially linked to clinical outcomes.

BACKGROUND: Oral tongue squamous cell carcinoma (OTSCC) is a highly aggressive malignancy characterized by frequent recurrence, poor survival with relatively few therapeutic options due to the late diagnosis in many cases. OBJECTIVES: Understanding the molecular pathways underlying OTSCC tumourigenesis and the discovery of diagnostic and/or prognostic biomarkers. METHODS: We performed high-throughput mutational analysis of 44 OTSCC formalin-fixed paraffin-embedded (FFPE) cases using the Cancer Hotspots Panel (CHP) v2 on the Ion Torrent™platform. We determined the frequency of human papilloma virus (HPV) using PCR and Epstein bar virus (EBV) positivity using immunohistochemistry. As a control for EBV infection we screened matched non-tumourous tissues. RESULTS: Sequencing analysis identified missense, nonsense and frameshift mutations in TP53 (66%), PIK3CA (27%), CDKN2A (25%), EGFR (18%), and PTEN (14%). Interestingly, no significant associations were found between damaging mutations and clinicopathological data. A total of 10/44 of the OTSCC samples (23%) tested was positive for HPV18 DNA. OTSCC patients with positive HPV infection had worse overall survival compared to HPV-negative cases as determined by Kaplan-Meier survival (p= 0.023). Furthermore, EBNA1 expression showed a strong tumour-enriched expression pattern in 20 out of 21 samples (95%) in the epithelial compartments of the tissues analysed. CONCLUSIONS: Taken together, this study highlights that the two most common events in OTSCC are TP53 mutations and EBV positivity. Helping to understand the contribution of TP53 mutations and EBV infection events could serve as useful biomarkers for OTSCC.