Prevalence and clinical outcomes of germline variants among patients with myeloid neoplasms

AIMS

Myeloid neoplasms (MNs) with germline predisposition have been recognised as a distinct entity. Emerging evidence suggests that sporadic myelodysplastic syndromes may also harbour undetected germline predispositions. We investigated germline alterations in a cohort of 122 adult Thai MNs.

METHODS

MN patients were recruited and tested for germline variants using deep targeted next-generation sequencing. The germline variant was filtered using American College of Medical Genetics classifications and then evaluated for the association with clinical characteristics and outcomes.

RESULTS

Our findings revealed pathogenic/likely pathogenic germline alterations in 12 (10%) of the patients. These germline lesions were commonly found in the DNA damage response pathway (n=6, 50%). We also identified novel deleterious FANCA A1219GfsTer59 variants in two patients diagnosed with secondary acute myeloid leukaemia (sAML) from aplastic anaemia and AML with myelodysplasia related. Among sAML, individuals with germline mutations had inferior overall survival compared with those with wild-type alleles (2 months vs 12 months) with HR 4.7 (95% CI 1.0 to 20), p=0.037. Therefore, the presence of pathogenic or likely pathogenic mutations may be linked to inferior survival outcomes.

CONCLUSIONS

Our study highlighted that the prevalence of germline predisposition in Southeast Asian populations is comparable to that in Caucasians. This underscores the importance of germline genetic testing within the Asian population.

Rare myxoid pleomorphic liposarcoma: a case report and literature review

We report a case of a middle-aged woman with a rapidly growing abdominal mass that was diagnosed as myxoid pleomorphic liposarcoma, a recently recognised, rare and aggressive subtype of liposarcoma. The tumour exhibits a combination of histological features from both myxoid liposarcoma and pleomorphic liposarcoma. Genetic analysis revealed mutations in TP53 and RB1, along with widespread loss of heterozygosity. However, no DDIT3 gene translocation or MDM2/CDK4 gene amplification was detected. These genetic characteristics can be used to distinguish this type of liposarcoma from others. Two unusual gene fusion/rearrangements, CREB5::TERT fusion and ETV1::LFNG rearrangement, were identified. The patient underwent complete removal of the tumour without the use of radiotherapy or chemotherapy. No recurrence was observed during the follow-up period of 18 months.

Gene of the month: VSTM2A

The V-set and transmembrane domain containing 2A (VSTM2A) gene is located on chromosome 7. In the physiological state, VSTM2A regulates preadipocyte cell differentiation. VSTM2A is highly expressed in normal human brain tissue and minimally expressed in other normal tissues. Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a distinct renal tumour subtype with signature chromosomal copy number alterations and an indolent outcome in the majority of cases. VSTM2A overexpression is highly enriched in this renal cancer subtype and has been shown to have potential diagnostic value in distinguishing MTSCC from renal tumours with overlapping histological appearances.

Clinicopathological and genetic analyses of pulmonary enteric adenocarcinoma

AIMS

Pulmonary enteric adenocarcinoma (PEAC) is a rare variant of pulmonary adenocarcinoma. Due to its rarity, few pathological and molecular studies have been performed on PEAC. We herein conducted clinicopathological, immunohistochemical and molecular analyses of PEAC with a focus on its differentiation from invasive mucinous adenocarcinoma (IMA).

METHODS

We examined the clinicopathological features of 16 cases of PEAC and performed a genetic analysis using next-generation sequencing (NGS). The results obtained were compared with those for IMA.

RESULTS

The average age of patients with PEAC (seven men and nine women) was 72.9 years. A comparison of clinical data on PEAC and IMA revealed no significant differences in age, sex or smoking history. Fifteen PEAC cases had dirty necrosis. Immunohistochemically, the positive rates for each antibody in PEAC were as follows: CK7, 88% (14/16); CK20, 81% (13/16); CDX2, 88% (14/16); p53, 69% (11/16); MUC1, 100% (16/16); MUC2, 19% (3/16); MUC5AC, 69% (11/16); MUC6, 19% (3/16). The positive rates for these antibodies in IMA were 100%, 87%, 0%, 7%, 93%, 0%, 100% and 80%, respectively. EGFR mutations, the MET exon 14 skipping mutation, BRAF mutations, the ALK fusion gene and ROS-1 fusion gene were not detected in any cases of PEAC or IMA. Among PEAC cases, NGS identified KRAS mutations in seven (44%, 7/16) and TP53 mutations in nine (56%, 9/16). Among IMA cases, the most commonly mutated gene was KRAS (90%).

CONCLUSIONS

The rates of dirty necrosis, immunopositivity for CDX2 and TP53 mutations were significantly higher, while that of KRAS mutations was significantly lower in PEAC cases than in IMA cases.

FOXL2: a gene central to ovarian function

The FOXL2 (forkhead box L2) gene is located on chromosome 3 and encodes for forkhead box (FOX) family of transcription factors which play a critical role in various biological processes. Germline FOXL2 mutations have been identified in blepharophimosis/ptosis/epicanthus inversus syndrome. The somatic missense mutation in FOXL2 (FOXL2 C134W) is now known to be the defining molecular feature of adult-type granulosa cell tumour of the ovary, present in over 90% of cases of this tumour type. Immunohistochemistry for FOXL2 is used as a marker of sex cord-stromal differentiation. However, expression is not restricted to lesions harbouring FOXL2 mutations, and it is positive in a variety of sex cord-stromal proliferations other than adult-type granulosa cell tumour.

Artificial intelligence (AI) molecular analysis tool assists in rapid treatment decision in lung cancer: a case report

Leptomeningeal involvement among non-small cell lung cancer (NSCLC) patients is an aggressive form of disease that requires quick and efficient treatment. In this case report, we describe a woman in her 40s with a presenting symptom of headache that ultimately was diagnosed as leptomeningeal spread from NSCLC adenocarcinoma. We identified EGFR mutation in less than 48 hours from the biopsy using imagene-artificial intelligence's real-time algorithmic solution on the pathological diagnostic slide.

Improving care of melanoma patients through efficient, integrated cellular-molecular pathology workflows using tissue samples with low tumour nuclear content

AIMS

The aim of this quality improvement project was to improve the turnaround time of B-raf proto-oncogene (BRAF) mutation testing in patients with malignant melanoma to support oncologists in making timely treatment decisions.

METHODS

This is a prospective in-house verification of the Idylla BRAF test as compared with DNA panel next-generation sequencing (NGS) performed at an external laboratory.

RESULTS

The Idylla BRAF test had an overall concordance of 95% compared with NGS. This was considered sufficiently good for use in patients with a poor performance status who were at risk of rapid clinical deterioration. Reliable results can be generated using the Idylla BRAF test in tissue sections with tumour neoplastic cell content below 50%. We present a multidisciplinary clinical care algorithm to support dual testing.

CONCLUSIONS

The Idylla BRAF test has the potential to make a significant positive impact on progression-free survival of malignant melanoma patients due to its rapid turnaround time. The Idylla BRAF test can be used as an adjunct to NGS for timely management of patients, particularly those with a poor performance status at presentation.

Gene of the month: PALB2

The partner and localiser of BRCA2 (PALB2) gene, located on chromosome 16, functions as a tumour suppressor that plays a critical role in homologous recombination repair after DNA double-strand breaks. It encodes proteins involved in the BRCA2 and BRCA1, and RAD51 pathways. Heterozygous germline mutations in PALB2 have been implicated in the development of breast, pancreatic and ovarian cancers. Whereas biallelic mutations of PALB2 have been associated with Fanconi anaaemia. Currently, 604 distinct PALB2 variants have been discovered. However, only 140 variants are thought to be pathogenic and approximately 400 are variants of unknown significance. Further studies are needed before the presence of PLAB2 mutations can be implemented as a routine clinical biomarker.