Hereditary persistence of alpha-fetoprotein

Role of Alpha-Fetoprotein in the Pathogenesis of Cancer

Alpha-fetoprotein (AFP) belongs to the albuminoid protein family and is considered as the fetal analog of serum albumin. This plasma protein is initially synthesized in the fetal liver and yolk sac and shows a maximum peak near the end of the first trimester. Later, concentrations begin to decline prenatally and drop precipitously after birth. This protein has three key ligand-binding pockets for interactions with various biomolecules. It contains multiple phosphorylation and acetylation sites for the regulation of physiological and pathophysiological states. High serum AFP titer is an established biomarker for yolk sac, embryonal and hepatocellular carcinoma. The present review critically analyzes the chemical nature, receptors, clinical implications, and therapeutic aspects of AFP, underpinning the development of different types of cancer.

Elevated Alpha-Fetoprotein in Infantile-Onset Niemann-Pick Type C Disease with Liver Involvement

Niemann-Pick disease type C (NPC) is a rare autosomal recessive neuro-visceral lipid storage disease. We describe nine cases of infantile-onset NPC with various genetic mutations in the NPC1 gene, which presented with neonatal cholestasis. Serum alpha-fetoprotein (AFP) levels were obtained as part of their workup during the first four months of life. In eight of nine (89%) patients, serum AFP demonstrated elevated levels. Seven infants displayed marked elevations, ranging from 4 to 300 times the upper limit for age-adjusted norms. In most patients, AFP levels peaked during the initial test and declined over time as cholestasis resolved. We conclude that elevated AFP levels are a common, although non-specific, marker for NPC-associated liver disease. These findings demonstrate the benefit of including AFP levels in the workup of neonatal liver disease, especially if there is accompanied cholestasis and if NPC is suspected.

Update on the applications and limitations of alpha-fetoprotein for hepatocellular carcinoma

Alpha-fetoprotein (AFP) is an oncofetal glycoprotein that has been used as a tumor marker for hepatocellular carcinoma (HCC) in combination with ultrasound and other imaging modalities. Its utility is limited because of both low sensitivity and specificity, and discrepancies among the different methods of measurements. Moreover, its accuracy varies according to patient characteristics and the AFP cut-off values used. Combination of AFP with novel biomarkers such as AFP-L3, Golgi specific membrane protein (GP73) and des-gamma-carboxyprothrombin significantly improved its accuracy in detecting HCC. Increased AFP level could also signify severity of hepatic destruction and subsequent regeneration and is commonly observed in patients with acute and chronic liver conditions and cirrhosis. Hereditary and other non-hepatic disorders can also cause AFP elevation.

Hereditary Persistence of Alpha-Fetoprotein in Chronic Liver Disease-Confusing Genes!

Alpha-fetoprotein (AFP) is a glycoprotein secreted by the embryonic liver and is expressed in tumours with high mitotic index such as hepatocellular carcinoma (HCC) and germ cell tumours. Detection of elevated AFP is strongly associated with underlying HCC or occasionally germ cell tumour. Modest elevation of AFP can be observed in patients with chronic viral hepatitis particularly with active replication. Very rarely, incidental detection of raised AFP in a genetically susceptible individuals has been reported in the absence of the underlying malignant process. This condition is termed as hereditary persistence of AFP (HPAFP), a rare disorder with an autosomal dominant pattern of inheritance. HPAFP should be suspected in patients with high AFP in the absence of radiological evidence of HCC or germ cell tumour. The diagnosis is confirmed by the identification of AFP gene mutation. AFP gene is located in the long arm of chromosome 4. The most common single-nucleotide polymorphism in HPAFP is 119 G > A, rs587776861, interestingly reported only in six family clusters worldwide. Despite being described as a benign disorder, its implication in patients with underlying chronic liver disease needs further clarification. Here, we describe 3 patients in their forties with chronic liver disease and persistently elevated levels of AFP, where genetic studies confirmed HPAFP. None of our patients had HCC despite extensive investigations.

Persistent α-Fetoprotein Elevation in Healthy Adults and Mutational Analysis of α-Fetoprotein Promoter, Enhancer, and Silencer Regions

Background/Aims

α-Fetoprotein (AFP) is normally <10 ng/mL in adults without malignancy or liver regeneration. However, hereditary or nonhereditary persistence of AFP in healthy adults may be encountered in clinical practice. This study describes four cases of persistent AFP elevation in healthy adults and investigates mutations in key transcription regulatory regions of the AFP gene as potential drivers of AFP overexpression.

Methods

Four healthy adults with persistently elevated AFP levels (12.1 to 186.1 ng/mL) for >1 year, and 20 controls with low AFP levels (<0.61 to 2.9 ng/mL) were included in the study. AFP levels were collected from the families of two of the patients. We sequenced five regions that are critical for AFP expression: a promoter, two enhancers, and two silencers.

Results

One of the two cases in which family information was represented is the first case of hereditary persistence of AFP in South Korea. Mutations related to AFP overexpression were not found in the transcription regulatory regions among the four patients.

Conclusions

Persistent AFP elevation is a heterogeneous condition with or without a hereditary pattern and may be caused by factors outside of transcription regulatory region changes. Further research on the mechanism of AFP elevation is needed.

Avoiding harmful procedures in patients with elevated α-fetoprotein concentrations: hereditary persistence of α-fetoprotein is an important and benign differential diagnosis!

BACKGROUND

Hereditary persistence of α-fetoprotein (AFP) is a rare but benign condition.

OBSERVATION

A 13-year-old girl presented with dysmenorrhoic complaints and irregular cycles. Diagnostic workup revealed a cystic lesion of the ovary and elevated AFP; β-human chorionic gonadotrophin was negative. Right-sided ovarectomy was performed. Postsurgery AFP concentration did not decline. The patient underwent further diagnostic workup with negative results. Histology revealed follicular cysts but no tumor. Finally, hereditary persistence of AFP was suspected and AFP testing was performed in the family.

CONCLUSIONS

It is important to include hereditary persistence of AFP in the differential diagnosis of elevated AFP concentrations to avoid harmful procedures.

High Alpha-Fetoprotein Persistence after Orchiectomy. On a Case of Uncommon Etiology

Background

The following report describes a case of inherited elevation of alpha-fetoprotein (AFP) in a young male suspected for testicular cancer. AFP shows very high values during fetal life. After birth the synthesis of AFP decreases dramatically, and only trace amounts are detected in the adult. From this age on, serum AFP can rise above normal in some diseases, e.g. liver disorders, and in some kind of tumors. A condition in which persistent high levels of AFP are found, named Hereditary Persistence of AFP [HPAFP), was first reported in 1983 by Ferguson-Smith, and then recorded in the literature only on eleven occasions till 2004. The occurrence of HPAFP may be underestimated. HPAFP can be easily confirmed by testing AFP levels in blood-related family members.

Methods

An elevated serum AFP (about 20 μg/mL) was found in a 27–year-old white man with an unremarkable medical history, who was concerned to have left testicular cancer. By our examination, his left testis was markedly reduced in size. β-HCG, LDH, and liver function were normal. Surgical inguinal exploration with testis and spermatic cord excision was carried out. Postoperative repeated AFP levels remained persistently elevated, in the range from 20 to 30 μg/mL. Careful evaluation for occult cancer showed no abnormality. Histology showed necrotic tissue and could not make a reliable diagnosis. A literature search was done using PubMed by key word “alpha-fetoprotein” and “elevation”. Thinking of a hereditary trait, we decided to screen patient's blood-related family members.

Results

AFP was found to be elevated in another four out of six relatives within three generations, unrelated to any disease. This pedigree was consistent with an autosomal dominant inheritance pattern.

Conclusions

HPAFP could mislead the physician. Failure to recognize HPAFP can lead to unsuitable treatments. The existence of this clinically benign condition needs to be considered in both children and adults with unexplained and persistent elevation of AFP, e.g. those diagnosed or suspected for germ cell tumor.

American Society of Clinical Oncology Clinical Practice Guideline on Uses of Serum Tumor Markers in Adult Males With Germ Cell Tumors

Purpose

To provide recommendations on appropriate uses for serum markers of germ cell tumors (GCTs).

Methods

Searches of MEDLINE and EMBASE identified relevant studies published in English. Primary outcomes included marker accuracy to predict the impact of decisions on outcomes. Secondary outcomes included proportions of patients with elevated markers and statistical tests of elevations as prognostic factors. An expert panel developed consensus guidelines based on data from 82 reports.

Results

No studies directly compared outcomes of decisions with versus without marker assays. The search identified few prospective studies and no randomized controlled trials; most were retrospective series. Lacking data on primary outcomes, most Panel recommendations are based on secondary outcomes (relapse rates and time to relapse).

Recommendations

The Panel recommended against using markers to screen for GCTs, to decide whether orchiectomy is indicated, or to select treatment for patients with cancer of unknown primary. To stage patients with testicular nonseminomas, the Panel recommended measuring three markers (α-fetoprotein [AFP], human chorionic gonadotropin [hCG], and lactate dehydrogenase [LDH]) before and after orchiectomy and before chemotherapy for those with extragonadal nonseminomas. They also recommended measuring AFP and hCG shortly before retroperitoneal lymph node dissection and at the start of each chemotherapy cycle for nonseminoma, and periodically to monitor for relapse. The Panel recommended measuring postorchiectomy hCG and LDH for patients with seminoma and preorchiectomy elevations. They recommended against using markers to guide or monitor treatment for seminoma or to detect relapse in those treated for stage I. However, they recommended measuring hCG and AFP to monitor for relapse in patients treated for advanced seminoma.