Association of Pancreatic Adenocarcinoma Location With DNA Damage Response Status and Response to Platinum-Based Therapy.

PURPOSE: Pancreatic adenocarcinoma is an aggressive disease with poor clinical outcomes. Primary pancreatic tumors originating from the head of the pancreas (H) have different prognostic implications than tumors arising from the body and tail (BT). This is thought to be largely due to anatomic differences, as molecular underpinnings of survival have not been fully explored. We hypothesized that differences in the primary site of H and BT tumors might account for differential molecular outcomes and response to chemotherapy. METHODS: Retrospective data from a single high-volume academic center were analyzed for hypothesis generation. A large-scale, real-world retrospective cohort of 2015 patients with next-generation sequencing (NGS) results were analyzed from a Real-World Evidence database. Progression-free survival (PFS) was evaluated from the initiation of first line of therapy for advanced disease until discontinuation because of progression. HR and P values were computed via Cox regression between first-line FOLFIRINOX and gemcitabine/nanoparticle albumin-bound (gem/nab) paclitaxel. Differences in frequencies of genomic alterations between H and BT were analyzed by Fisher's exact test. RESULTS: Genomic alterations in the DNA damage response (DDR) pathway (such as BRCA1, BRCA2, and PALB2) were enriched (unadjusted P value = .00244) in BT tumors (21.7% of 618) relative to H tumors (15.6% of 942) where BRCA2 was a top contributor within this pathway. Median PFS in BT tumors on first-line FOLFIRINOX was longer than first line gem/nab-paclitaxel (P = .006393); this difference was not identified in H tumors (P = .5546). CONCLUSION: DDR pathway alterations including BRCA1/BRCA2/PALB2 are known predictors of increased benefit from platinum-based chemotherapy. NGS testing for germline and somatic mutations remains important in pancreatic ductal adenocarcinoma, especially in BT tumors where DDR pathway alterations may be more common than in H tumors.

Identification of dual STRN-NTRK2 rearrangements in a high grade sarcoma, with good clinical response to first-line larotrectinib therapy.

BACKGROUND: Among the three NTRK genes, NTRK2 possesses a tremendous structural complexity and involves tumorigenesis of several types of tumors. To date, only STRN and RBPMS are identified in the fusion with NTRK2 in adult soft tissue tumors. More recently, the highly selective Trk tyrosine kinases inhibitors, including larotrectinib and entrectinib, have shown significant efficacy for treating tumors harboring NTRK fusions and were approved by FDA. CASE PRESENTATION: We report a case of sarcoma in a 35-year-old female harboring two STRN-NTRK2 gene fusions, with a good clinical response to first-line larotrectinib treatment. Core biopsy of the 16.5 cm gluteal mass showed a high-grade mesenchymal neoplasm with features reminiscent of a solitary fibrous tumor, but negative for STAT6. In-house next-generation sequencing gene fusion panel showed two in-frame STRN-NTRK2 fusions, which contain the same 5' partner sequence (exon 1-3) of STRN, and the 3' fusion partner starting from either the exon 15 or the exon 16 of NTRK2. Due to the large size and location of the tumor, first-line neoadjuvant therapy with larotrectinib was initiated. The patient has an excellent clinical response with an 83% tumor size reduction by imaging. The tumor was subsequently completely resected. After 130 days, larotrectinib was reinitiated for lung metastasis (up to 7 cm), and a complete resolution was achieved. When compared with NTRK1 and NTRK3, NTRK2 fusions are the least common. Of note, the only other report in the literature on NRTK2 fusion-positive sarcoma also showed solitary fibrous tumor (SFT)-like morphology, and the patient responded well to larotrectinib as the second line adjuvant therapy. CONCLUSIONS: In conclusion, the identification of NTRK2 fusions in patients with soft tissue tumors could significantly improve the clinical outcome through selective NTRK inhibitor therapy, especially in the first-line setting. Prompt RNA-based NGS testing at initial diagnosis may benefit these patients. Our case is among the first few in the literature on NTRK2 fusion sarcoma with first-line larotrectinib therapy in the primary and metastatic setting, with good clinical response and minimal side effects.

Larotrectinib efficacy and safety in adult patients with tropomyosin receptor kinase fusion sarcomas.

BACKGROUND: Larotrectinib, a first-in-class, highly selective tropomyosin receptor kinase (TRK) inhibitor, has demonstrated efficacy in adult and pediatric patients with various solid tumors harboring NTRK gene fusions. This subset analysis focuses on the efficacy and safety of larotrectinib in an expanded cohort of adult patients with TRK fusion sarcomas. METHODS: Patients (≥18 years old) with sarcomas harboring NTRK gene fusions were identified from three clinical trials. Patients received larotrectinib 100 mg orally twice daily. Response was investigator-assessed per RECIST v1.1. Data cutoff was July 20, 2021. RESULTS: At the data cutoff, 36 adult patients with TRK fusion sarcomas had initiated larotrectinib therapy: two (6%) patients had bone sarcomas, four (11%) had gastrointestinal stromal tumors, and 30 (83%) had soft tissue sarcomas. All patients were evaluable for response and demonstrated an objective response rate of 58% (95% confidence interval, 41-74). Patients responded well to larotrectinib regardless of number of prior lines of therapy. Adverse events (AEs) were mostly grade 1/2. Grade 3 treatment-emergent AEs (TEAEs) occurred in 15 (42%) patients. There were no grade 4 TEAEs. Two grade 5 TEAEs were reported, neither of which were considered related to larotrectinib. Four (11%) patients permanently discontinued treatment due to TEAEs. CONCLUSIONS: Larotrectinib demonstrated robust and durable responses, extended survival benefit, and a favorable safety profile in adult patients with TRK fusion sarcomas with longer follow-up. These results continue to demonstrate that testing for NTRK gene fusions should be incorporated into the clinical management of adult patients with various types of sarcomas. PLAIN LANGUAGE SUMMARY: Tropomyosin receptor kinase (TRK) fusion proteins result from translocations involving the NTRK gene and cause cancer in a range of tumor types. Larotrectinib is an agent that specifically targets TRK fusion proteins and is approved for the treatment of patients with TRK fusion cancer. This study looked at how well larotrectinib worked in adult patients with sarcomas caused by TRK fusion proteins. Over half of patients had a durable response to larotrectinib, with no unexpected side effects. These results show that larotrectinib is safe and effective in adult patients with TRK fusion sarcomas.

Metabolic Pathways and Targets in Chondrosarcoma.

Chondrosarcomas are the second most common primary bone malignancy. Chondrosarcomas are characterized by the production of cartilaginous matrix and are generally resistant to radiation and chemotherapy and the outcomes are overall poor. Hence, there is strong interest in determining mechanisms of cancer aggressiveness and therapeutic resistance in chondrosarcomas. There are metabolic alterations in chondrosarcoma that are linked to the epigenetic state and tumor microenvironment that drive treatment resistance. This review focuses on metabolic changes in chondrosarcoma, and the relationship between signaling via isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2), hedgehog, PI3K-mTOR-AKT, and SRC, as well as histone acetylation and angiogenesis. Also, potential treatment strategies targeting metabolism will be discussed including potential synergy with immunotherapies.

TERT gene rearrangement in chordomas and comparison to other TERT-rearranged solid tumors.

Chordomas are rare, slow-growing neoplasms thought to arise from the foetal notochord remnant. A limited number of studies that examined the mutational profiles in chordomas identified potential driver mutations, including duplication in the TBXT gene (encoding brachyury), mutations in the PI3K/AKT signaling pathway, and loss of the CDKN2A gene. Most chordomas remain without clear driver mutations, and no fusion genes have been identified thus far. We discovered a novel TERT in-frame fusion involving RPH3AL (exon 5) and TERT (exon 2) in the index chordoma case. We screened a discovery cohort of 18 additional chordoma cases for TERT gene rearrangement by FISH, in which TERT rearrangement was identified in one additional case. In our independent, validation cohort of 36 chordomas, no TERT rearrangement was observed by FISH. Immunohistochemistry optimized for nuclear TERT expression showed at least focal TERT expression in 40/55 (72.7%) chordomas. Selected cases underwent molecular genetic profiling, which showed low tumor mutational burdens (TMBs) without obvious driver oncogenic mutations. We next examined a cohort of 1,913 solid tumor patients for TERT rearrangements, and TERT fusions involving exon 2 were observed in 7/1,913 (0.4%) cases. The seven tumors comprised five glial tumors, and two poorly differentiated carcinomas. In contrast to chordomas, the other TERT-rearranged tumors were notable for higher TMBs, frequent TP53 mutations (6/7) and presence of other driver oncogenic mutations, including a concurrent fusion (TRIM24-MET). In conclusion, TERT gene rearrangements are seen in a small subset (2/55, 3.6%) of chordomas. In contrast to other TERT-rearranged tumors, where the TERT rearrangements are likely passenger events, the possibility that TERT protein overexpression representing a key event in chordoma tumorigenesis is left open.

Excision repair cross-complementing group-1 (ERCC1) induction kinetics and polymorphism are markers of inferior outcome in patients with colorectal cancer treated with oxaliplatin.

BACKGROUND: ERCC1, a component of nucleotide excision repair pathway, is known to repair DNA breaks induced by platinum drugs. We sought to ascertain if ERCC1 expression dynamics and a single nucleotide polymorphism (SNP) rs11615 are biomarkers of sensitivity to oxaliplatin therapy in patients with colorectal cancer (CRC). METHODS: Western blot and qPCR for ERCC1 expression was performed from PBMCs isolated from patients receiving oxaliplatin-based therapy at specified timepoints. DNA was also isolated from 59 biorepository specimens for SNP analysis. Clinical benefit was determined using progression free survival (PFS) for metastatic CRC. RESULTS: ERCC1 was induced in PBMC in response to oxaliplatin in 13/25 patients with mCRC (52%). Median PFS with ERCC1 induction was 190d compared to 237d in non-induced patients (HR 2.35, CI 1.005-5.479; p=0.0182). ERCC1 rs11615 SNP analysis revealed that 43.3% harbored C/C, 41.2%-T/C and 15.5%-T/T genotype. Median PFS was significantly lower with C/C or T/C (211 and 196d) compared to T/T (590d; p=0.0310). CONCLUSIONS: ERCC1 was induced in a sub-population of patients undergoing oxaliplatin treatment, which was associated with poorer outcome, suggesting this could serve as a marker of oxaliplatin response. C/C or C/T genotype in ERCC1 rs11615 locus decreased benefit from oxaliplatin.

A Routine Laboratory Data-Based Model for Predicting Recurrence After Curative Resection of Stage II Colorectal Cancer.

Background: Use of chemotherapy in stage II colorectal cancer (CRC) is controversial because it improves survival only in some patients. We aimed to develop a statistical model using routine and readily available blood tests to predict the prognosis of patients with stage II CRC and to identify which patients are likely to benefit from chemotherapy. Methods: We divided 422 patients with stage II CRC into a training and a testing set. The association of routine laboratory variables and disease-free survival (DFS) was analyzed. A prognostic model was developed incorporating clinically relevant laboratory variables with demographic and tumor characteristics. A prognostic score was derived by calculating the sum of each variable weighted by its regression coefficient in the model. Model performance was evaluated by constructing receiver operating characteristic curves and calculating the area under the curve (AUC). Results: Significant associations were seen between 5 laboratory variables and patient DFS in univariate analyses. After stepwise selection, 3 variables (carcinoembryonic antigen, hemoglobin, creatinine) were retained in the multivariate model with an AUC of 0.75. Compared with patients with a low prognostic score, those with a medium and high prognostic score had a 1.99- and 4.78-fold increased risk of recurrence, respectively. The results from the training set were validated in the testing set. Moreover, chemotherapy significantly improved DFS in high-risk patients, but not in low- and medium-risk patients. Conclusions: A routine laboratory variable-based model may help predict DFS of patients with stage II CRC and identify high-risk patients more likely to benefit from chemotherapy.