Atypical Papillary Thyroid Carcinoma with Squamous Metaplasia and RET/NRAS/TERT/PIK3CA Mutations: A Case Report

Background: Papillary thyroid carcinoma (PTC) with squamous metaplasia is a relatively rare and special subtype adenocarcinoma of thyroid which involves multiple genetic changes. We reported a rare case of atypical PTC with squamous metaplasia and RET/NRAS/TERT/PIK3CA mutations which was confirmed after surgical resection pathologically. Case summary: A 2.5×2.5×2 cm3, smooth, hard, clear boundaries and solid nodule on the left thyroid gland was found on relevant physical examination of the patient. And then, the unilateral radical resection of thyroid carcinoma was performed after diagnosing. The tumor cells were squamous metaplasia and arranged in structures with diffuse growth pattern microscopically. At high magnification, stretched nucleus, nuclear grooves and internuclear pseudoinclusions in tumor cells were detected, and the follicular epithelium cells were atypical. Immunohistochemical staining shown strong positiveness of CK19, TTF-1, P40 and Galectin-3, partial positiveness of TG of tumor cells and negativeness of Calcitonin, which could exclude medullary thyroid carcinoma (MTC). Furthermore, first generation sequencing of 18 PTC related genes techniques shown RET, NRAS, TERT and PIK3CA was mutated. Conclusion: Genetic detection is vital to the diagnosis of thyroid adenocarcinoma, especially for the PTC with atypical morphology or rare metaplasia

PIK3CA Mutations in Diffuse Gliomas: An Update on Molecular Stratification, Prognosis, Recurrence, and Aggressiveness

Introduction: PIK3CA is one of the most mutated oncogenes in solid tumors. In breast cancer (ER-positive, HER2-negative), these events represent a predictive biomarker of response to alpelisib. In glioblastomas (GBM), PIK3CA mutations were described as early constitutive events. Here, we investigated PIK3CA mutational profile across glioma molecular subgroups and its relevance during glioma recurrence. Furthermore, PIK3CA mutations’ effect in PI3K pathway, prognosis, and response to therapy was also explored. Material and Methods: Exons 10 and 21 of PIK3CA mutations were evaluated in 394 gliomas and 19 glioma recurrences from Instituto Português de Oncologia Lisboa Francisco Gentil (IPOLFG) and compared with The Cancer Genome Atlas (TCGA) data. TIMER2.0 and NetMHCpan4.1 were used to assess the immune-microenvironment contribution. Results: PIK3CA mutations were identified among all glioma subgroups, although with no impact on their stratification or prognosis. In both cohorts (IPOLFG and TCGA), PIK3CA mutation frequencies in IDH-mutant and IDH-wild-type GBM were similar (IPOLFG: 9% and 3%; TCGA: 8% and 2%). These mutations were not mutually exclusive with PTEN deletion and EGFR amplification. Despite their reduced frequency, we discovered PIK3CA mutations were maintained during glioma recurrence regardless of administered therapies. The immune microenvironment might not contribute to this phenotype as PIK3CA mutations did not influence immune cell infiltration. Conclusions: Despite the absence of a predominant effect in glioma stratification, PIK3CA mutations were maintained during glioma recurrence, possibly contributing to glioma cell survival, representing promising therapeutic targets in recurrent glioma. Nevertheless, understanding the potential synergistic effects between PIK3CA mutations, PTEN deletion, and EGFR amplification is pivotal to targeted therapies’ efficiency.

Benchmarking Outcomes after Ablative Radiotherapy for Molecularly Characterized Intrahepatic Cholangiocarcinoma

We have previously shown that ablative radiotherapy (A-RT) with a biologically effective dose (BED10) ≥ 80.5 Gy for patients with unresectable intrahepatic cholangiocarcinoma (ICC) is associated with longer survival. Despite recent large-scale sequencing efforts in ICC, outcomes following RT based on genetic alterations have not been described. We reviewed records of 156 consecutive patients treated with A-RT for unresectable ICC from 2008 to 2020. For 114 patients (73%), next-generation sequencing provided molecular profiles. The overall survival (OS), local control (LC), and distant metastasis-free survival (DMFS) were estimated using the Kaplan–Meier method. Univariate and multivariable Cox analyses were used to determine the associations with the outcomes. The median tumor size was 7.3 (range: 2.2–18.2) cm. The portal vein thrombus (PVT) was present in 10%. The RT median BED10 was 98 Gy (range: 81–144 Gy). The median (95% confidence interval) follow-up was 58 (42–104) months from diagnosis and 39 (33–74) months from RT. The median OS was 32 (29–35) months after diagnosis and 20 (16–24) months after RT. The one-year OS, LC, and intrahepatic DMFS were 73% (65–80%), 81% (73–87%), and 34% (26–42%). The most common mutations were in IDH1 (25%), TP53 (22%), ARID1A (19%), and FGFR2 (13%). Upon multivariable analysis, the factors associated with death included worse performance status, larger tumor, metastatic disease, higher CA 19-9, PVT, satellitosis, and IDH1 and PIK3CA mutations. TP53 mutation was associated with local failure. Further investigation into the prognostic value of individual mutations and combinations thereof is warranted.

TP53 Gain-of-Function and Non–Gain-of-Function Mutations Are Differentially Associated With Sidedness-Dependent Prognosis in Metastatic Colorectal Cancer

PURPOSE To examine the association of gain-of-function (GOF) and non–gain-of-function (non-GOF) TP53 mutations with prognosis of metastatic right-sided (RCC) versus left-sided colorectal cancer (LCC). METHODS This cohort study included patients with metastatic colorectal cancer (CRC) who had next-generation sequencing performed from November 2017 to January 2021. We defined R175H, R248W, R248Q, R249S, R273H, R273L, and R282W as GOF and all other mutp53 as non-GOF. We used Cox regression modeling to examine the association between GOF and non-GOF mutp53 and overall survival (OS), adjusting for age, sex, ethnicity, performance status, Charlson comorbidity index and receipt of chemotherapy. RESULTS Of total 1,043 patients, 735 had tumors with mutp53 and 308 had wild-type p53 (wtp53). GOF was associated with worse OS than non-GOF mutp53 only in LCC (hazard ratio [HR] = 1.66 [95% CI, 1.20 to 2.29]), but not in RCC (HR = 0.79 [95% CI, 0.49 to 1.26]). Importantly, RCC was associated with worse OS than LCC only in the subset of patients whose CRC carried non-GOF (HR = 1.76 [95% CI, 1.30 to 2.39]), but not GOF mutp53 (HR = 0.92 [95% CI, 0.55 to 1.53]) or wtp53 (HR = 0.88 [95% CI, 0.60 to 1.28]). These associations were largely unchanged after also adjusting for RAS, BRAF, and PIK3CA mutations, and microsatellite instability-high. CONCLUSION Poorer survival of patients with metastatic RCC versus LCC appeared to be restricted to the subset with non-GOF mutp53, whereas GOF versus non-GOF mutp53 was associated with poorer survival only among patients with LCC. This approach of collectively classifying mutp53 into GOF and non-GOF provides new insight for prognostic stratification and for understanding the mechanism of sidedness-dependent prognosis. If confirmed, future CRC clinical trials may benefit from incorporating this approach.

CTNI-22. A PHASE 0/1 ‘TRIGGER’ TRIAL OF RIBOCICLIB PLUS EVEROLIMUS IN RECURRENT HIGH-GRADE GLIOMA

BACKGROUND mTOR activation is a mechanism of resistance in CDK4/6 targeting. We evaluated tumor pharmacokinetics (PK) and tumor pharmacodynamics (PD) of combined CDK4/6 and mTOR inhibition in recurrent high-grade glioma (HGG) patients. METHODS Recurrent HGG patients with (1) intact RB, (2) CDKN2A/B deletion or CDK4/6 amplification, and (3) PTEN loss or PIK3CA mutations receive five days of presurgical ribociclib plus everolimus prior to resection at 2, 8 or 24 hours after the final dose. Beginning at 400mg QD ribociclib plus 2.5mg QD everolimus, six dose-escalations summit at 600mg QD plus 60mg QW. Gadolinium [Gd]-enhancing and nonenhancing tumor regions, CSF, and plasma are collected. Total and unbound drug concentrations are determined using validated LC-MS/MS methods. RB and S6 phosphorylation are compared to matched archival tissue. To select patients for a therapeutic expansion phase of combined drug therapy, the protocol includes a PK ‘trigger’ (i.e., for each drug, unbound concentration in Gd-nonenhancing tumor > 5-fold biochemical IC50) and a PD ‘trigger’ (i.e., for each tumor, > 30% decrease in pRB and pS6). RESULTS 21 patients with WHO Grade III (n=2) and IV (n=19) gliomas were enrolled into the Phase 0 component of the study. No dose-limiting toxicities were observed. In Gd-nonenhancing tumor regions, the median unbound concentration of ribociclib was 719 nM, whereas unbound everolimus tumor concentrations were undetectable. Across all dose-levels, 62% (13/21) and 22% (5/21) of tumors demonstrated decreased tumor RB and S6 phosphorylation, respectively. Tumor proliferation (MIB-1) was decreased in 67% (14/21) of all patients. No patients qualified for the therapeutic expansion phase. CONCLUSION In adult HGG, ribociclib achieves pharmacologically-relevant concentrations in Gd-nonenhancing tumor whereas everolimus exhibits no meaningful tumor penetration. These findings support further clinical development of ribociclib, but not everolimus, for the treatment of high-grade glioma patients.

Predictive role of CCND1, FGFR1 gene amplifications and PIK3CA mutations for endocrine therapy of primary metastatic breast cancer

Background. More than half of breast carcinomas express estrogen and progesterone receptors (ER and PR) and remain estrogen-dependent. Endocrine therapy with inhibitors of the estrogen cascade allows long-term and effective control of the disease in a significant number of patients, however, some patients demonstrate primary, and the majority - secondary resistance to such treatment. The aim of the study was to evaluate the predictive significance of the CCND1 and FGFR1 gene amplifications and PIK3CA mutations for endocrine therapy. Materials and methods. The study included 138 women with ER-positive primary metastatic breast cancer (BC) who received hormone therapy with aromatase inhibitors (AIs) (n = 69), tamoxifen (n = 65), goserelin (n = 2), or a combination of goserelin and tamoxifen (n = 2) as the first line treatment. CCND1 and FGFR1 gene amplifications were tested by digital droplet PCR, while mutations in exons 7, 9, and 20 of the PIK3CA gene were determined using high-resolution melting analysis and allele-specific PCR. We analyzed the associations between the presence of the mentioned genetic lesions, progression-free-survival (PFS) and response to treatment. Results. Amplifications of CCND1 and FGFR1 genes were identified in 24 (17.9%) and 28 (20.9%) of 134 successfully tested cases, respectively; 9 tumors were positive for both alterations. Amplifications were more prevalent in less differentiated tumors (p = 0.018). CCND1 amplification was associated with shorter PFS in patients receiving aromatase inhibitors (16.0 months vs. 32.4 months, HR = 3.16 [95% CI: 1.26-7.93], p = 0.014). FGFR1 status did not significantly affect PFS of AI-treated women, however, partial regress as a result of AI implementation was less frequent in FGFR1-amplified BC as compared to cases with normal FGFR1 copy number (p = 0.031). The frequency of PIK3CA mutations was 40.2% (49/122). They were more often observed in smaller tumors (p = 0.034), in PR-positive carcinomas (p = 0.012), and in cases with more extensive metastatic involvement (p = 0.029). The presence of PIK3CA mutations did not affect the results of treatment with AI or tamoxifen. Conclusion The presence of CCND1 and/or FGFR1 amplification is associated with worse results of AI therapy of metastatic breast cancer.

Comparing Biomarkers for Predicting Pathological Responses to Neoadjuvant Therapy in HER2-Positive Breast Cancer: A Systematic Review and Meta-Analysis

IntroductionThe predictive strength and accuracy of some biomarkers for the pathological complete response (pCR) to neoadjuvant therapy for HER2-positive breast cancer remain unclear. This study aimed to compare the accuracy of the HER2-enriched subtype and the presence of PIK3CA mutations, namely, TILs, HRs, and Ki-67, in predicting the pCR to HER2-positive breast cancer therapy.MethodsWe screened studies that included pCR predicted by one of the following biomarkers: the HER2-enriched subtype and the presence of PIK3CA mutations, TILs, HRs, or Ki-67. We then calculated the pooled sensitivity, specificity, positive and negative predictive values (PPVs and NPVs, respectively), and positive and negative likelihood ratios (LRs). Summary receiver operating characteristic (SROC) curves and areas under the curve (AUCs) were used to estimate the diagnostic accuracy.ResultsThe pooled estimates of sensitivity and specificity for the HER2-enriched subtype and the presence of PIK3CA mutations, namely, TILs, HRs, and Ki-67, were 0.66 and 0.62, 0.85 and 0.27, 0.49 and 0.61, 0.54 and 0.64, and 0.68 and 0.51, respectively. The AUC of the HER2-enriched subtype was significantly higher (0.71) than those for the presence of TILs (0.59, p = 0.003), HRs (0.65, p = 0.003), and Ki-67 (0.62, p = 0.005). The AUC of the HER2-enriched subtype had a tendency to be higher than that of the presence of PIK3CA mutations (0.58, p = 0.220). Moreover, it had relatively high PPV (0.58) and LR+ (1.77), similar NPV (0.73), and low LR− (0.54) compared with the other four biomarkers.ConclusionsThe HER2-enriched subtype has a moderate breast cancer diagnostic accuracy, which is better than those of the presence of PIK3CA mutations, TILs, HRs, and Ki-67.