Lynch syndrome or hereditary non polyposis colorectal cancer (HNPCC) in a moroccan family: Case report

Introduction and importance

Colorectal cancer is a major global health problem. In 5% of cases, a genetic predisposition to cancer's syndrome is the etiology, such as Lynch syndrome. The population prevalence of Lynch syndrome has been estimated at 1/440. The objectives of this study are to show the interest of the oncogenetic consultation in the management of patients with suspicion of Lynch syndrome.

Case presentation

It is a 70-year-old patient with a family history of different neoplasms. The patient has also been followed for an adenocarcinoma of the colon. An oncogenetic consultation was indicated, which led to the diagnosis of Lynch syndrome, according to the Amsterdam II criteria. A study of the MisMatch Repair genes was requested, to allow a pre-symptomatic diagnosis of apparented subjects at risk, and thus to also allow monitoring and early diagnosis of neoplasms or prophylactic measures.

Discussion

Lynch syndrome is one of the most common cancer susceptibility syndromes. A constitutional deleterious mutation in one of the DNA MisMatch Repair genes, is responsible for nearly 70% of cases of this syndrome. The oncogenetic consultation and the identification of the genetics cause, makes it possible to set up specific monitoring and to offer a pre-symptomatic test to all major relatives of the index case.

Conclusion

This medical observation shows the benefit of the oncogenetic consultation, if a genetic predisposition to cancer's syndrome is suspected. The diagnostic of this predisposition and monitoring of the propositus and his exposed, like in Lynch syndrome will help in the early management of cancers, specially colorectal cancer and endometrial adenocarcinoma.

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Lynch syndrome in a moroccan family: A case report:

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It shows the interest of a oncogenetic consultation if we suspect a hereditary predisposition to cancers.

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And the necessity of the surveillance of the propositus and his exposed relatives, to make possible an early management of cancers.

13q interstitial deletion in a moroccan child with hereditary retinoblastoma and intellectual disability: A case report

Retinoblastoma is the most common malignant tumor of the eye in children (incidence:1/15,000 to 1/20,000 births), with a sex ratio of 1,5/1. Retinoblastoma, in its inherited form, is a disease caused by a syndrome of genetic predisposition to cancer. The RB1 gene, a tumor suppressor gene, is localized at 13q14. This case report shows the indication of the cytogenetic analysis in the management of patients with retinoblastoma, and the interest of a genetic counseling. We report the medical observation of a five and a half years old patient who was followed in the medical genetic's department for intellectual disability: associated with facial dysmorphia. The cytogenetic study objectified the presence of an interstitial deletion of the long arm of chromosome 13: 46, XX, del (13) (q14q22). A genetic counseling, with study of the karyotype of the parents is planned, specially to search for a balanced insertion: 13q14 insertion and deletion. In addition, the patient has been followed since the age of 9 months at the pediatric ophthalmology department for a bilateral retinoblastoma, in remission. A subject carry in constitutional mutation of the RB1 gene has a greater than 90% risk of developing retinoblastoma, and moreover has a genetic predisposition to secondary tumors. This medical observation shows the benefit of the constitutional cytogenetic study for patients with retinoblastoma, in particular in the event of bilateral retinoblastoma. The monitoring of psychomotor development must supplement the ophthalmological monitoring of these patients, with a systematic genetic counseling.

Evaluation of a novel multiplex RT-qPCR assay for the quantification of leukemia-associated BCR-ABL1 translocation

Although monitoring of BCR-ABL1 translocation has become an established practice in the management of chronic myeloid leukemia (CML), the detection limit of the BCR-ABL1 transcripts needs more standardization. The aim of the present study was to evaluate the clinical performances of a novel assay for the quantification of BCR-ABL1 fusion transcripts (e13a2 and e14a2) and ABL1 in a single reaction. This assay is based on the real-time reverse transcription polymerase chain reaction (RT-qPCR) in multiplex format. In a retrospective comparative clinical study performed in a reference laboratory, RNA was extracted from 48 CML patient blood samples with various BCR-ABL1/ABL1 ratios and RT-qPCR was performed using either MAScIR assay or the RT-qPCR simplex reference assay used in routine clinical testing. The comparative clinical results showed high qualitative and quantitative concordance (correlation coefficient >0.95) between MAScIR and the reference assays. The present study illustrates the utility of MAScIR assay as a sensitive, rapid, and cost-effective quantitative device to monitor the BCR-ABL1 ratios by RT-qPCR on whole blood of diagnosed Philadelphia chromosome-positive (Ph+) leukemia patients. This test could be used as an aid in the assessment of molecular response to available treatments.

Quantitative real-time polymerase chain reaction as an efficient molecular tool for detecting minimal residual disease in Moroccan chronic myeloid leukemia patients

Chronic myeloid leukemia (CML) is characterized by BCR-ABL translocation and an increased number and migration of immature myeloid cells into the peripheral blood. The detection limit of the BCR-ABL transcript, particularly after treatment, is controversial. In the present study, we used quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR) to monitor BCR-ABL expression in Moroccan CML patients undergoing imatinib treatment, and compared the results with those of conventional PCR and fluorescence in situ hybridization (FISH). The aim of this study was to establish a new molecular tool for in vitro diagnosis of CML. In a retrospective comparative analysis, 20 CML Moroccan patients who had received imatinib treatment (N = 20) were analyzed by real-time PCR, conventional RT-PCR, and FISH. Half of the samples analyzed (N = 10) were positive for BCR-ABL gene expression, while the other half (N = 10) were negative according to conventional PCR. Interestingly, 5 of the 10 samples shown to be negative by conventional PCR showed positive expression of the BCR-ABL gene according to RT-qPCR. The RT-qPCR results were confirmed by FISH, which revealed a high concordance (100%) rate. We found that real-time RT-qPCR is more reliable and should be used in Moroccan biomedical analysis laboratories to monitor CML progression, particularly for minimal residual disease, following imatinib treatment.

Effect of interaction of glutathione S-transferases (T1 and M1) on the hematologic and cytogenetic responses in chronic myeloid leukemia patients treated with imatinib

The glutathione S-transferases (GSTs) are phase II xenobiotic metabolizing enzymes known to be involved in the detoxification of carcinogens and anticancer drugs. Individual genetic variation linked to inherited polymorphisms of GSTT1 and GSTM1 leading to a complete loss of enzyme activity could expose subjects to develop cancer or to induce drug resistance. Indeed, despite the impressive results obtained with the imatinib, some patients with chronic myeloid leukemia (CML) fail to achieve the expected results or develop resistance. The present study aimed to examine the impact of GSTT1 and GSTM1 polymorphisms on the response to imatinib in patients with CML. Multiplex polymerase chain reaction was used to detect the genotypes of GSTT1 and GSTM1 in 60 CML patients. We found that side effects were more frequent in patients carrying GSTT1 null when compared to GSTT1 present carriers (31 vs. 16.6 %; χ (2) = 6.2; p = 0.013). The loss of hematologic response was statistically greater in patients carrying the combined genotype GSTT1 present/GSTM1 present (26.3 %) when compared to GSTT1 null/GSTM1 present (12.8 %), GSTT1 present/GSTM1 null (8.3 %) and GSTT1 null/GSTM1 null (0 %), (χ (2) = 18.85; p < 0.001). The complete cytogenetic response was higher in patients harboring the GSTT1 null/GSTM1 null (75 %) compared with GSTT1 null/GSTM1 present (55.6 %), GSTT1 present/GSTM1 null (50 %) and GSTT1 present/GSTM1 present (47.8). On the other hand, the frequency of none cytogenetic responders was more common in patients carrying GSTT1 present/GSTM1 present (34.8 %) when compared to other genotype combinations (χ (2) = 20.99; p = 0.05). Moreover, the GSTT1 present/GSTM1 present appeared to be associated with a final dose of 600 or 800 mg of imatinib, but not significantly. Based on these findings, we find that the interaction between GSTT1 and GSTM1 seems to influence treatment outcome in patients with CML. Therefore, further investigations are required to confirm these results, for better genotype-phenotype correlation.