Assessment of Circulating Tumor Cells in Colorectal Cancer as an Adjunctive Non-invasive Diagnostic Method.

BACKGROUND: Colorectal cancer (CRC) is a significant contributor to cancer-related morbidity and mortality. Biopsy remains the gold standard for CRC diagnosis, but invasive testing may not be preferred as an initial diagnostic procedure. Therefore, alternative non-invasive approaches are needed. Circulating tumor cells (CTC) present in the bloodstream have great potential as a non-invasive diagnostic marker for CRC patients. This study aimed to assess the diagnostic potential of CTC in CRC as an adjunctive diagnostic method using a subjective manual identification method and laser capture microdissection at 40x magnification. METHODS: A cross-sectional study was conducted on adult patients suspected to have CRC at Dr. Cipto Mangunkusumo National General Hospital, Jakarta, between November 2020 and March 2021. CTC analysis was performed using the negative selection immunomagnetic method with Easysep™ and the CD44 mesenchymal tumor marker. The identification and quantification of CTC were conducted manually and subjectively, with three repetitions of cell counting per field of view at 40x magnification. RESULTS: Of 80 subjects, 77.5% were diagnosed with CRC, while 7.5% and 15% exhibited adenomatous polyps and inflammatory/hyperplastic polyps, respectively. The diagnostic analysis of CTC for detecting CRC (compared to polyps) using a CTC cutoff point of >1.5 cells/mL suggested sensitivity, specificity, and positive predictive value (PPV) of 50%, 88.89%, and 93.94%. Additionally, the negative predictive value (NPV), as well as the positive and negative likelihood ratio (PLR and NLR) were 34.04%, 4.5, and 0.56, respectively. The subjective manual identification and quantification of CTC were performed at 40x magnification using laser capture microdissection. CONCLUSION: This study assessed the diagnostic potential of CTC examination in CRC as an adjunctive diagnostic method using the subjective manual identification method and laser capture microdissection at 40x magnification. Despite the limitations associated with subjective cell counting, the results showed 50% sensitivity and 88.89% specificity in diagnosing CRC. Further studies are needed to optimize the manual identification process and validate the clinical utility of CTC analysis in CRC patients.

TP53 and EGFR Mutational Status in Thymoma: A Genetic Sequencing Study.

BACKGROUND AND OBJECTIVE: Thymoma is a rare malignant tumor that usually with an indolent presentation, which was falsely assumed to be benign previously. The tumor suppressor P53 (TP53) and EGFR gene mutate most frequently in human cancers. We tried to investigate the presence of TP53 and EGFR mutations among thymoma patients referred to an Indonesian referral respiratory hospital and to discuss its potential role in thymoma management and prognosis. MATERIAL AND METHODS: Surgically resected tumor tissues were collected from thymoma patients and then underwent genomic analysis. PCR was performed on the extracted Paraffinized  DNA to amplify exon 6 of TP53 and exons 18, 19, and 21 of EGFR. The evaluation of mutational status was done using direct sequencing and sequence analysis of purified PCR products. RESULTS: Among 27 collected samples, TP53 exon 6 mutation, namely  missense mutation and nonsense mutation, was observed in two samples (7.4%). EGFR exon 18 mutation, namely E709K and nonsense mutation, was found in 2 samples (7.4%). An intronic mutation in EGFR exon 19 (3.7%) and exon 21 (3.7%) was observed in one sample. CONCLUSION: TP53 and EGFR mutations were not most frequent, so it seems that these genes are not involved in the pathogenesis of thymoma in Indonesian patients. Nevertheless, we found two samples with a significant mutation in p53 and EGFR genes, suggesting further research on thymoma prognostification and targeted therapy.

The Absence of Mutations in the Exon 2 KRAS Gene in Several Ethnic Groups in North Sumatra May Not the Main Factor for Lung Cancer.

BACKGROUND: Rat Sarcoma (RAS) protein encoded Guanosine Triphosphate (GTP-ase) activity, known as a switch of cell proliferation. The mutation of this protein alters the early stage of carcinogenesis and along with the interaction with other oncogene drivers and environmental factors affect the clinical characteristics and prognosis in cancer patients, particularly lung cancer. OBJECTIVE: This study aims to determine the Kristen Rat Sarcoma (KRAS) mutation in lung cancer patients in North Sumatera and evaluate factors that might contribute in the development of lung cancer in the absence of KRAS mutation. METHODS: This was a retrospective cohort study enrolled 44 subjects age > 18 year with the diagnosis of lung cancer. Histopathology preparation was obtained from surgery, bronchoscopy, and percutaneus needle biopsy then formed as paraffin-block. KRAS mutation was analyzed using Polymerase Chain Reaction (PCR) method with specific primer of exon 2 for evaluating the expression of RAS protein then continued with Sanger Sequencing Method at 12th and 13th codon. RESULTS: The majority of subjects were male, age > 40 years old, bataknese, heavy smoker, with Adenocarcinoma. Almost all the subjects showed the expression of exon 2 of RAS protein in PCR examinations. However, Sequencing analysis using Bioedit Software, BLASTs and Finch T showed GGT GGC as protein base 219-224 which represented 12th and 13th Codon 12 and 13. The results interpreted there was no mutations of exon 2 of KRAS in North Sumatera Population. CONCLUSION: The absence of KRAS mutation in exon 2 in several ethnics in North Sumatera populations was not the main factors of lung cancer.