Characteristics of TP53 germline variants and their correlation with Li-Fraumeni syndrome or Li-Fraumeni-like syndrome in Chinese tumor patients

Pediatric-type high-grade gliomas with PDGFRA amplification in adult patients with Li-Fraumeni syndrome: clinical and molecular characterization of three cases

Li-Fraumeni syndrome (LFS) is an autosomal dominant tumor predisposition syndrome caused by heterozygous germline mutations or deletions in the TP53 tumor suppressor gene. Central nervous system tumors, such as choroid plexus tumors, medulloblastomas, and diffuse gliomas, are frequently found in patients with LFS. Although molecular profiles of diffuse gliomas that develop in pediatric patients with LFS have been elucidated, those in adults are limited. Recently, diffuse gliomas have been divided into pediatric- and adult-type gliomas, based on their distinct molecular profiles. In the present study, we investigated the molecular profiles of high-grade gliomas in three adults with LFS. These tumors revealed characteristic histopathological findings of high-grade glioma or glioblastoma and harbored wild-type IDH1/2 according to whole exome sequencing (WES). However, these tumors did not exhibit the key molecular alterations of glioblastoma, IDH-wildtype such as TERT promoter mutation, EGFR amplification, or chromosome 7 gain and 10 loss. Although WES revealed no other characteristic gene mutations or copy number alterations in high-grade gliomas, such as those in histone H3 genes, PDGFRA amplification was found in all three cases together with uniparental disomy of chromosome 17p, where the TP53 gene is located. DNA methylation analyses revealed that all tumors exhibited DNA methylation profiles similar to those of pediatric-type high-grade glioma H3-wildtype and IDH-wildtype (pHGG H3-/IDH-wt), RTK1 subtype. These data suggest that high-grade gliomas developed in adult patients with LFS may be involved in pHGG H3-/IDH-wt. PDGFRA and homozygous alterations in TP53 may play pivotal roles in the development of this type of glioma in adult patients with LFS.

Lessons learnt from the clinico-genomic profiling of families with Li Fraumeni syndrome at a tertiary care centre in North India

Li Fraumeni syndrome (LFS) is an inherited cancer predisposition syndrome due to TP53 gene mutation. There is sparse literature on LFS in the Indian population. We conducted a retrospective study of patients diagnosed with LFS and their family members, registered at our Medical Oncology Department between September 2015 and 2022. 9 LFS families consisted of 29 patients diagnosed currently or historically with malignancies including 9 index cases and 20 first or second-degree relatives. Of these 29 patients, 7 (24.1%) patients developed their first malignancy before the age of 18 years, 15 (51.7%) were diagnosed between 18and and 60 years, and 7 (24.1%) were diagnosed at age more than 60 years. A total of 31 cancers occurred among the families, including 2 index cases who had metachronous malignancies. Each family had a median of three cancers (range 2-5); sarcoma (n = 12, 38.7% of total cancers) and breast cancer (n = 6, 19.3% of total cancers) being the commonest malignancies. Germline TP53 mutations were documented among 11 patients with cancers and 6 asymptomatic carriers. Of these nine mutations, the most common types were missense (n = 6, 66.6%) and nonsense (n = 2, 22.2%), and the commonest aberration was replacement of arginine with histidine (n = 4, 44.4%). Eight (88.8%) families met either classical or Chompret's diagnostic criteria and two (22.2%) satisfied both. Two (22.2%) families fit the diagnostic criteria prior to onset of malignancy in the index cases but were untested till the index cases presented to us. Four mutation carriers from three families are undergoing screening as per the Toronto protocol. No new malignancies have been detected so far during the mean surveillance duration of 14 months. The diagnosis of LFS has socio-economic implications for patients and their families. Delay in genetic testing misses out a crucial window wherein asymptomatic carriers could initiate surveillance in a timely fashion. Greater awareness on LFS and genetic testing in Indian patients is warranted for better management of this hereditary condition.

Identification of nine mutant genes and establishment of three prediction models of organ tropism metastases of non-small cell lung cancer

BACKGROUND

Most Non-small cell lung cancer (NSCLC) patients tend to have metastases at the initial diagnosis. However, limited knowledge has been established regarding which factors, are associated with its metastases. This study aims to identify more biomarkers associated with its organ tropism metastasis and to establish models for prediction of its metastatic organs.

METHODS

We performed targeted next-generation sequencing (NGS) to detect genes related to lung cancer in 272 patients with primary advanced NSCLC from Northeast China. We adopted Fisher test, multivariate logistic regression analysis to identify metastasis-related gene mutations and to establish prediction models.

RESULTS

Mutations of EGFR (p = 0.0003, OR = 2.554) (especially EGFR L858R [p = 0.02, OR = 2.009]), ATM (p = 0.008, OR = 11.032), and JAK2 (p = 0.009, OR = Inf) were positively and of TP53 exon4mut (p = 0.001, OR = 0.173) was negatively correlated with lung metastasis, and those of CSF1R (p = 0.01, OR = Inf), KIT (p = 0.03, OR = 4.746), MYC (p = 0.05, OR = 7.938), and ERBB2 (p = 0.02, OR = 2.666) were positively correlated with pleural dissemination; those of TP53 (p = 0.01, OR = 0.417) was negatively, while of SMAD4 (p = 0.03, OR = 4.957) was positively correlated with brain metastasis of NSCLC. Additionally, smoking history (p = 0.004, OR = 0.004) was negatively correlated with pleural dissemination of NSCLC. Furthermore, models for prediction of lung metastasis (AUC = 0.706), pleural dissemination (AUC = 0.651), and brane metastasis (AUC = 0.629) were established.

CONCLUSION

Taken together, this study revealed nine mutant genes and smoking history associated with organ tropism metastases of NSCLC and provided three models for the prediction of metastatic organs. This study enables us to predict the organs to which non-small cell lung cancer metastasizes before it does develop.