Systemic AA Amyloidosis Caused by Inflammatory Hepatocellular Adenoma

Benign liver tumours: understanding molecular physiology to adapt clinical management

Improvements in understanding the pathophysiology of the different benign liver nodules have refined their nosological classification. New criteria have been identified using imaging, histology and molecular analyses for a precise diagnosis of these tumours. Improvement in the classification of liver tumours provides a more accurate prediction of disease progression and has modified patient management. Haemangioma and focal nodular hyperplasia, the most common benign liver tumours that develop in the absence of chronic liver disease, are usually easy to diagnose on imaging and do not require specific treatment. However, hepatocellular adenomas and cirrhotic macronodules can be difficult to discriminate from hepatocellular carcinoma. The molecular subtyping of hepatocellular adenomas in five major subgroups defined by HNF1A inactivation, β-catenin mutation in exon 3 or exon 7/8, and activation of inflammatory or Hedgehog pathways helps to identify the tumours at risk of malignant transformation or bleeding. New clinical, biological and molecular tools have gradually been included in diagnostic and treatment algorithms to classify benign liver tumours and improve patient management. This Review aims to explain the main pathogenic mechanisms of benign liver tumours and how this knowledge could influence clinical practice.

Hepatocellular adenoma: Where are we now?

Hepatocellular adenoma (HCA) is a benign hepatocellular neoplasm, commonly occurs in young women with a history of oral contraceptive use. Complications including hemorrhage and malignant transformation necessitate the need for a thorough understanding of the underlying molecular signatures in this entity. Recent molecular studies have significantly expanded our knowledge of HCAs. The well-developed phenotype-genotype classification system improves clinical management through identifying “high risk” subtype of HCAs. In this article, we attempt to provide updated information on clinical, pathologic and molecular features of each subtype of HCAs.

Preneoplastic lesions in the liver: Molecular insights and relevance for clinical practice

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the most frequent primary liver cancers, accounting for approximately 80% and 15%, respectively. HCC carcinogenesis occurs mostly in cirrhosis and is a complex multi-step process, from precancerous lesions (low-grade and high-grade dysplastic nodules) to progressed HCC. During the different stages of liver carcinogenesis, there is an accumulation of pathological, genetic and epigenetic changes leading to initiation, malignant transformation and finally tumour progression. In contrast, a small subset of HCC occurs in normal liver from the transformation of hepatocellular adenoma (HCA), a benign hepatocellular tumour. The recent molecular classification enables to stratify HCAs according to their risk of complication, in particular malignant transformation, associated with mutations in exon 3 of the catenin beta 1 (CTNNB1) gene. Cholangiocarcinoma (CCA) derives from the multistep malignant transformation of preneoplastic lesions, like biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB), for which a pre-operative diagnosis remains difficult. Different genetic alterations are involved in BilIN and IPNB progression, leading to the development of tubular or intestinal adenocarcinoma. The aims of this review are to describe the main clinical and molecular features of preneoplastic lesions leading to the development of HCC and CCA, their implications in clinical practice and the perspectives for future research.

Mosaic IL6ST variant inducing constitutive GP130 cytokine receptor signaling as a cause of neonatal onset immunodeficiency with autoinflammation and dysmorphy

Interleukin-6 signal transducer (IL6ST) encodes the GP130 protein which transduces the proinflammatory signaling of the IL6 cytokine family through Janus kinase signal transducers and activators of transcription pathway (JAK/STAT) activation. Biallelic loss-of-function IL6ST variants cause autosomal recessive hyper-IgE syndrome or a variant of the Stuve-Wiedemann syndrome. Somatic gain-of-function IL6ST mutations, in particular, small monoallelic in-frame deletions of which the most prevalent is the IL6ST Ser187_Tyr190del, are an established cause of inflammatory hepatocellular tumors, but so far, no disease caused by such mutations present constitutively has been described. Herein, we report a pediatric proband with a novel syndrome of neonatal onset immunodeficiency with autoinflammation and dysmorphy associated with the IL6ST Tyr186_Tyr190del variant present constitutively. Tyr186_Tyr190del was found by exome sequencing and was shown to be de novo (absent in proband's parents and siblings) and mosaic (present in approximately 15-40% of cells depending on the tissue studied-blood, urine sediment, hair bulbs and buccal swab). Functional studies were performed in the Epstein-Barr virus-immortalized patient's B cell lymphoblastoid cell line, which carried the variant in approximately 95% of the cells. Western blot showed that the patient's cells exhibited constitutive hyperphosphorylation of Tyr705 in STAT3, which is indicative of IL6-independent activation of GP130. Interestingly, the STAT3 phosphorylation could be inhibited with ruxolitinib as well as tofacitinib, which are clinically approved JAK1 and JAK3 (to lesser extent JAK2 and JAK1) inhibitors, respectively. Given our results and the recent reports of ruxolitinib and tofacitinib use for the treatment of diseases caused by direct activation of STAT3 or STAT1, we speculate that these drugs may be effective in the treatment of our patient's condition.

Cervical cancer of the uterus complicated by renal AA amyloidosis

Cervical cancer of the uterus rarely develops systemic secondary amyloidosis. We present the case of a 66-year-old female patient who manifested systemic amyloid A (AA) amyloidosis in the kidney, digestive tract, and cervix of the uterus, secondary to cervical cancer. She exhibited nephrotic syndrome, intractable diarrhea, and mild fever 3 months after she underwent an extended hysterectomy with postoperative cisplatin-based chemotherapy and whole pelvic irradiation. Further examinations revealed AA amyloidosis of the kidney and colon and cytomegalovirus infection in the colon. AA amyloid deposition was positive in the resected tissues of uterine cancer. The patient was diagnosed with systemic AA amyloidosis consecutive to cervical cancer. Despite a decrease in urinary protein after antiviral therapy, it increased 14 months later with neither apparent symptoms nor an increase in tumor marker. A second renal biopsy revealed AA amyloidosis of the kidney. Subsequent investigations revealed the recurrence of cervical cancer in the lung, liver, and lymph nodes. This case report indicated that AA amyloidosis would complicate cervical cancer and recur even after resection of neoplasm owing to other stimulation. Moreover, urine protein could be a marker for cancer relapse in known cases of cancer-derived AA amyloidosis.

Recurrent chromosomal rearrangements of ROS1, FRK and IL6 activating JAK/STAT pathway in inflammatory hepatocellular adenomas

BACKGROUND

Inflammatory hepatocellular adenomas (IHCAs) are benign liver tumours characterised by an activation of the janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway caused by oncogenic activating mutations. However, a subset of IHCA lacks of identified mutation explaining the inflammatory phenotype.

METHODS

657 hepatocellular adenomas developed in 504 patients were analysed for gene expression of 17 genes and for mutations in seven genes by sequencing. 22 non-mutated IHCAs were analysed by whole-exome and/or RNA sequencing.

RESULTS

We identified 296 IHCA (45%), 81% of them were mutated in either IL6ST (61%), FRK (8%), STAT3 (5%), GNAS (3%) or JAK1 (2%). Among non-mutated IHCA, RNA sequencing identified recurrent chromosome rearrangement involving ROS1, FRK or IL6 genes. ROS1 fusions were identified in 8 IHCA, involving C-terminal part of genes highly expressed in the liver (PLG, RBP4, APOB) fused with exon 33-35 to 43 of ROS1 including the tyrosine kinase domain. In two cases a truncated ROS1 transcript from exon 36 to 43 was identified. ROS1 rearrangements were validated by fluorescence in situ hybridisation (FISH) and led to ROS1 overexpression. Among the 5 IHCA with FRK rearrangements, 5 different partners were identified (MIA3, MIA2, LMO7, PLEKHA5, SEC16B) fused to a common region in FRK that included exon 3-8. No overexpression of FRK transcript was detected but the predicted chimeric proteins lacked the auto-inhibitory SH2-SH3 domains. In two IHCA, we identified truncated 3'UTR of IL6 associated with overexpression of the transcript.

CONCLUSION

Recurrent chromosomal alterations involving ROS1, FRK or IL6 genes lead to activation of the JAK/STAT pathway in IHCAs.

Causes of AA amyloidosis: a systematic review

From a clinical perspective, there is a need for a reliable and comprehensive list of diseases causing AA amyloidosis. This list could guide clinicians in the evaluation of patients with AA amyloidosis in whom an obvious cause is lacking. In this systematic review, a PubMed, Embase and Web of Science literature search were performed on causes of AA amyloidosis published in the last four decades. Initially, 4066 unique titles were identified, but only 795 full-text articles and letters were finally selected for analysis. Titles were excluded because of non-AA type of amyloidosis, language, no full-text publication or irrelevance. Hundred and fifty diseases were initially reported to be associated with the development of AA amyloidosis. The presence of AA amyloid was proven in 208 articles (26% of all) of which 140 (67%) showed a strong association with an underlying disease process. Disease associations were categorized and 48 were listed as strong, 19 as weak, 23 as unclear, and 60 as unlikely. Most newly described diseases are not really unexpected because they often cause longstanding inflammation. Based on the spectrum of identified causes, a pragmatic diagnostic approach is proposed for the AA amyloidosis patient in whom an obvious underlying disease is lacking.

The role of telomeres and telomerase in cirrhosis and liver cancer

Telomerase is a key enzyme for cell survival that prevents telomere shortening and the subsequent cellular senescence that is observed after many rounds of cell division. In contrast, inactivation of telomerase is observed in most cells of the adult liver. Absence of telomerase activity and shortening of telomeres has been implicated in hepatocyte senescence and the development of cirrhosis, a chronic liver disease that can lead to hepatocellular carcinoma (HCC) development. During hepatocarcinogenesis, telomerase reactivation is required to enable the uncontrolled cell proliferation that leads to malignant transformation and HCC development. Part of the telomerase complex, telomerase reverse transcriptase, is encoded by TERT, and several mechanisms of telomerase reactivation have been described in HCC that include somatic TERT promoter mutations, TERT amplification, TERT translocation and viral insertion into the TERT gene. An understanding of the role of telomeres and telomerase in HCC development is important to develop future targeted therapies and improve survival of this disease. In this Review, the roles of telomeres and telomerase in liver carcinogenesis are discussed, in addition to their potential translation to clinical practice as biomarkers and therapeutic targets.

A case of protein-losing gastroenteropathy caused by systemic AA amyloidosis secondary to undifferentiated carcinoma of unknown primary origin

We report the case of a 61-year-old woman with Kartagener syndrome who presented with a 3-month history of chronic watery diarrhoea and severe hypoalbuminaemia. Histopathological examination of duodenum and large intestine biopsies showed amyloid A (AA) amyloid deposition. Scintigraphy and alpha-1 anti-trypsin clearance evaluations revealed protein-losing gastroenteropathy. Computed tomography with contrast and positron emission tomography showed a pelvic mass with multiple para-aortic lymph node enlargement. We suspected protein-losing gastroenteropathy secondary to AA amyloid produced related to malignant tumours. Following tumour resection, histopathological examination of the lesion revealed undifferentiated carcinoma of unknown origin. Postoperatively, the patient’s nutritional condition improved. There has been no recurrence of protein-losing gastroenteropathy 6 months postoperatively. This is the first report of protein-losing gastroenteropathy and AA amyloidosis secondary to undifferentiated carcinoma. Early recognition and intervention could increase the likelihood of amyloidosis remission.