People living in high background radiation areas (HBRAs) possibly develop the radioadaptive response (RAR) phenomenon. The Mamuju area in West Sulawesi Indonesia is known as an HBRA in Indonesia due to its high natural uranium contents. It is possible that RAR has developed in Mamuju inhabitants. To prove this hypothesis, here in this study, evaluation of the individual radiosensitivity in the inhabitants of Takandeang Village, Mamuju, was conducted using G 2 micronucleus (MN) assay. Association between blood groups and TP53 Arg72Pro polymorphism with individual radiosensitivity was also evaluated in this study. Using G 2 MN assay, we assessed the individual radiosensitivity of Takandeang Village inhabitants and control samples. For each sample, three parameters were calculated. The spontaneous (baseline) MN number, MN number after 0.5 Gy in vitro irradiation, and radiation-induced MN were calculated to predict the individual radiosensitivity. The radiation-induced MN was defined by subtracting the spontaneous MN number from the MN number after irradiation. The mean and SD of the number of micronuclei induced by radiation found in control group (CG) was set as the cutoff value to determine the individual radiosensitivity in all samples. The occurrence of a radiation-induced MN value higher than the mean CG + 1SD CG was scored as 1, indicating a milder radiosensitive phenotype, whereas a result higher than the mean CG + 2SD CG was scored as 2, and indicated a more severe radiosensitive phenotype. When the individual value was lower than the mean CG + 1SD CG, a score of 0 was attributed to the tested subject. The results showed that four individuals in Takandeang Village inhabitants had a milder radiosensitive phenotype, while the others were categorized as normal radiosensitive. A similar finding was also found in control samples. Our study failed to find any correlation between radiosensitivity and either blood group or the TP53 Arg72Pro polymorphism. Overall, our study revealed the possibility of RAR phenomena in Takandeang Village inhabitants. Further investigation using a different point of radiation dose value and larger sample number should be performed to validate this study results.Journal homepage: http://aij.batan.go.id

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X-rays repair cross-complementing group 1 (XRCC1) gene is one of the gene that plays an important role in base excision repair system (BER) and DNA repair both single and double strand breaks. Individuals with XRCC1 exon 10 (Arg399Gln) gene polymorphisms and carrying 399Gln allele variants (A allele) have a greater risk of DNA damage than their wildtype, 399Arg. The aim of this study was to examine the genotype frequencies of single nucleotide polymorphisms (SNPs) of XRCC1 exon 10 among medical radiation workers. This study involved 77 samples from several hospitals in Indonesia. Genotyping of XRCC1 exon 10 gene polymorphism was performed using PCR-RFLP. Individuals carrying A allele had lower frequency than that is carrying their wildtype of 399Arg (0.39 vs. 0.61). The results indicated that 39% of medical radiation workers had a risk of repair efficiency of DNA damage and might influence an individual's risk of cancer. Ionizing radiation induces many types of damage to DNA, requiring multiple repair pathways to restore genomics integrity. Other important genes/pathways, especially those for DNA doublestrand break repair, might also play a role and should be further investigated. Furthermore, polymorphisms leading to inefficient DNA repair might also be associated with late reactions to radiotherapy. ABSTRAK Gen X-rays repair cross-complementing group1 (XRCC1) adalah salah satu gen yang berperan penting dalam BER dan perbaikan DNA baik kerusakan untai tunggal maupun ganda. Individu dengan polimorfisme gen XRCC1 exon 10 (Arg399Gln) dan membawa varian alel 399Gln (alel A) memiliki risiko kerusakan DNA lebih besar daripada wildtype, 399Arg. Tujuan dari penelitian ini adalah untuk menguji frekuensi genotip polimorfisme nukleotida tunggal (SNPs) dari XRCC1 exon 10 pada petugas radiasi medis. Penelitian ini melibatkan 77 sampel dari beberapa rumah sakit di Indonesia. Uji genotip polimorfisme gen XRCC1 ekson 10 dilakukan dengan menggunakan teknik PCR-RFLP. Individu yang membawa alel A memiliki frekuensi lebih rendah daripada yang membawa wildtype 399Arg (0,39 vs 0,61). Hasil ini menunjukkan bahwa 39% pekerja radiasi medis memiliki risiko berkurangnya efisiensi perbaikan kerusakan DNA dan dapat mempengaruhi risiko kanker seseorang. Radiasi pengion menginduksi berbagai jenis kerusakan pada DNA dan membutuhkan beberapa jalur perbaikan untuk memulihkan integritas genomik. Gen/jalur penting lainnya, terutama untuk perbaikan untai ganda DNA, mungkin juga berperan dan perlu diteliti lebih lanjut. Selanjutnya, polimorfisme yang menyebabkan perbaikan DNA yang tidak efisien juga terkait dengan respon terhadap radioterapi.

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Background: The variability of clinical response in radiotherapy (RT) patients revealed that individual radiosensitivity exists in humans. Although several techniques for radiosensitivity assessment are available, fluorescence in situ hybridization (FISH) has proven to be the most reliable cytogenetic technique. This study will review the use of three-color FISH to evaluate the individual radiosensitivity in cancer patients, particularly breast and prostate cancer patients. Also, it will explain factors that should be considered when using this assay in RT patients.Methods: We used the “radiosensitivity”, “fluorescence in situ hybridization”, “FISH”, and “cancer” as medical subject headings. Non-English articles were excluded. Only articles written in English with a full-text PDF format could be found and using three-color FISH for individual radiosensitivity prediction in radiotherapy patients as subjects were included in this review.Results: : In total, 1,905 articles were retrieved from PubMed and PubMed Central databases from 1990 to 2020. The articles were screened, and those that met the inclusion criteria and did not meet the exclusion criteria were reviewed. Finally, we evaluated eight articles in this reviewConclusions: Appropriate assays such as three-color FISH for individual radiosensitivity assessment could optimize the effectiveness of RT treatment and predict the severity of normal tissue toxicity reactions in RT patients.