The Clinical and Molecular Profile of Lung Cancer Patients Harboring the TP53 R337H Germline Variant in a Brazilian Cancer Center: The Possible Mechanism of Carcinogenesis.

In southern and southeastern Brazil, the TP53 founder variant c.1010G>A (R337H) has been previously documented with a prevalence of 0.3% within the general population and linked to a heightened incidence of lung adenocarcinomas (LUADs). In the present investigation, we cover clinical and molecular characterizations of lung cancer patients from the Brazilian Li-Fraumeni Syndrome Study (BLISS) database. Among the 175 diagnosed malignant neoplasms, 28 (16%) were classified as LUADs, predominantly occurring in females (68%), aged above 50 years, and never-smokers (78.6%). Significantly, LUADs manifested as the initial clinical presentation of Li-Fraumeni Syndrome in 78.6% of cases. Molecular profiling was available for 20 patients, with 14 (70%) revealing EGFR family alterations. In total, 23 alterations in cancer driver genes were identified, comprising 7 actionable mutations and 4 linked to resistance against systemic treatments. In conclusion, the carriers of TP53 R337H demonstrate a predisposition to LUAD development. Furthermore, our results indicate that environmental pollution potentially impacts the carcinogenesis of lung tumors in the carriers of TP53 R337H.

TP53-associated early breast cancer: new observations from a large cohort.

BACKGROUND: A recent large, well-annotated international cohort of patients with Li-Fraumeni syndrome and early-stage breast cancer was examined for shared features. METHODS: This multicenter cohort study included women with a germline TP53 pathogenic or likely pathogenic variant and nonmetastatic breast cancer diagnosed between 2002 and 2022. Clinical and genetic data were obtained from institutional registries and clinical charts. Descriptive statistics were used to summarize proportions, and differences were assessed using χ2 or Wilcoxon rank sum tests. Metachronous contralateral breast cancer risk, radiation-induced sarcoma risk, and recurrence-free survival were analyzed using the Kaplan-Meier methodology. RESULTS: Among 227 women who met study criteria, the median age of first breast cancer diagnosis was 37 years (range = 21-71), 11.9% presented with bilateral synchronous breast cancer, and 18.1% had ductal carcinoma in situ only. In total, 166 (73.1%) patients underwent mastectomies, including 67 bilateral mastectomies as first breast cancer surgery. Among those patients with retained breast tissue, the contralateral breast cancer rate was 25.3% at 5 years. Among 186 invasive tumors, 72.1% were stages I to II, 48.9% were node negative, and the most common subtypes were hormone receptor-positive/HER2-negative (40.9%) and hormone receptor positive/HER2 positive (34.4%). At a median follow-up of 69.9 months (interquartile range = 32.6-125.9), invasive hormone receptor-positive/HER2-negative disease had the highest recurrence risk among the subtypes (5-year recurrence-free survival = 61.1%, P = .001). Among those who received radiation therapy (n = 79), the 5-year radiation-induced sarcoma rate was 4.8%. CONCLUSION: We observed high rates of ductal carcinoma in situ, hormone receptor-positive, and HER2-positive breast cancers, with a worse outcome in the hormone receptor-positive/HER2-negative luminal tumors, despite appropriate treatment. Confirmation of these findings in further studies could have implications for breast cancer care in those with Li-Fraumeni syndrome.

PREMM5 distinguishes sporadic from Lynch syndrome-associated MMR-deficient/MSI-high colorectal cancer.

Current algorithms for diagnosing Lynch syndrome (LS) include multistep molecular tumor tests to distinguish LS-associated from sporadic colorectal cancer (CRC), which add cost and complexity to the evaluation. We hypothesized that PREMM5, a clinical LS prediction tool, could be an alternative approach to screen for LS, thereby lessening the need for specialized molecular diagnostics. We reviewed a consecutively ascertained institutional cohort of 1058 CRC patients on whom pathologic and clinical data were available, including prior LS germline testing. Data from MMR-D/MSI-H CRC patients were reviewed and PREMM5 scores were calculated for each individual. Using a PREMM5 score cutoff ≥ 2.5% to characterize the need for germline testing, we determined the rate of pathogenic/likely pathogenic germline variants (PGVs) in LS genes in patients with PREMM5 scores ≥ 2.5% versus < 2.5%. Sensitivity and negative predictive values (NPV) of PREMM5 were calculated for all MMR-D/MSI-H CRC patients, and those with MLH1-deficient CRC. MMR IHC and/or MSI results were available on 572/1058 cases. We identified 74/572 (12.9%) cases as MMR-D/MSI-H, of which 28/74 (37.8%) harbored a LS PGV. 11/49 (22.4%) patients with MLH1-deficient CRC harbored a LS PGV. PREMM5 had 100% sensitivity (95% CI: 87.7-100 for any MMR-D/MSI-H; 95% CI: 71.5-100 for MLH1-deficient CRC) and 100% NPV (95% CI: 83.2-100 for any MMR-D/MSI-H; 95% CI: 82.4-100 for MLH1-deficient CRC) for identifying LS PGVs in these cohorts. PREMM5 accurately distinguishes LS- from non-LS-associated MMR-D/MSI-H CRC without additional somatic molecular testing. These findings are particularly relevant for limited-resource settings where advanced molecular diagnostics may be unavailable.