Diagnostic utility of SALL4 in extragonadal yolk sac tumors: an immunohistochemical study of 59 cases with comparison to placental-like alkaline phosphatase, alpha-fetoprotein, and glypican-3

SALL4 as a Useful Marker for the Distinction of Various Gestational Trophoblastic Disease Subtypes: Choriocarcinoma From Other Trophoblastic Lesions and Early Complete Hydatidiform Mole From Partial Mole and NonMolar Villi

The distinction between choriocarcinoma and residual trophoblastic cell proliferation from a complete hydatidiform mole/invasive mole (CHM/IM) without villi is challenging on curettage materials. We investigated whether SALL4 immunostaining could help differentiate various gestational trophoblastic diseases. Placental site nodules (PSN; n=10), atypical PSN (APSN; n=8), placental site trophoblastic tumors (PSTT; n=9), epithelioid trophoblastic tumors (ETT; n=5), gestational choriocarcinomas (n=31), partial hydatidiform moles (PHM; n=13), CHM/IM (n=47), and nonmolar products of conception (POC) (n=26) were included. SALL4 immunostaining was quantified (0 [1% to 10%], [11% to 100%]) and characterized (scattered single-cell or clustered nuclear positivity) in 2 locations: cytotrophoblast/intermediate trophoblast and villous stromal fibroblasts. A diffuse (11% to 100%) and clustered pattern of SALL4 immunostaining in cytotrophoblast/intermediate trophoblast was statistically associated with choriocarcinomas (74.2%, 23/31) as compared with PSN (0/10; P <0.0001), APSN (0/8; P =0.0002), PSTT (0/9; P <0.0001), ETT (0/5; P =0.0034), PHM (0/13; P <0.0001), CHM/IM (0/47; P <0.0001), and nonmolar POC (0/26; P <0.0001). Most nonchoriocarcinoma samples showed no SALL4 expression; when present, it was of low level (1% to 10%) and with a scattered single-cell staining in 3/9 PSTT (33%), 1/13 PHM (7.7%), 19/47 CHM/IM (40%), and 1/26 nonmolar POC (1.7%). These results were confirmed using a validation cohort. In addition, 66% (31/47) of CHM/IM villous stromal fibroblasts showed SALL4 expression (11% to 100%) (all before 14 gestational weeks), whereas this level of expression was never observed in PHM (0/13), nor in nonmolar POC (0/26; P <0.0001). Finally, a clustered and >10% SALL4 immunostaining in cytotrophoblast/intermediate trophoblast favors choriocarcinoma diagnosis. SALL4 expression in >10% villous stromal fibroblasts before 14 gestational weeks favors CHM/IM rather than PHM and nonmolar POC.

Yolk Sac Tumor of the Liver: An Important Differential for Liver Mass with Elevated Serum Alpha-Fetoprotein in the Pediatric Population

Introduction: Yolk sac tumor (YST) is a malignant germ cell tumor with 10-15% arising in extragonadal sites. Methods: A search through our institution's database from January 01, 1990, to December 31, 2020, for "yolk sac tumor" or "endodermal sinus tumor" and "liver". Results: Our search yielded three cases. A 20-month-old girl with a liver mass and serum alpha-fetoprotein (AFP) level of 46558.0 ng/mL. The neoplasm was papillary with Schiller-Duval bodies. A 2-year-old boy with hepatic masses and adrenal mass with a serum AFP of 106,604.5 ng/mL. Numerous Schiller-Duval bodies were present. A 7-month-old girl with a liver mass, lung nodules, and retroperitoneal masses. Serum AFP was in the 800s ng/mL. Hepatoid and microcystic YST were mixed with hepatoblastoma (HBL). All three cases were positive for CAM5.2, SALL4, Glypican-3, beta-catenin, and AFP. Conclusion: Hepatic yolk sac tumor should be considered in the differential of a liver mass in pediatric patients with elevated AFP.

Germ cell tumors in children

Pediatric germ cell tumors represent a rare but biologically diverse group of neoplasms arising from pluripotent primordial germ cells. The 2022 edition of the WHO Classification of Pediatric Tumors introduced the first organ independent classification of germ cell tumors, reflecting advances in molecular biology, histopathology, and clinical practice. This review highlights the key changes, including the refined distinctions between the different subtypes. These updates enhance diagnostic accuracy and provide a framework for understanding age-dependent differences in tumor biology and behavior. Emphasis is placed on integrating the new classification into multidisciplinary care, particularly in addressing diagnostic challenges in pre- and post-pubertal-type germ cell tumors. By bridging the gap between histopathology and oncology, the updated classification represents a pivotal step forward in improving outcomes for children with germ cell tumors.

An intracranial yolk sac tumor with initial symptom of hemorrhage in the basal ganglia: a case report

We report a case and follow-up of an adult male with intracranial yolk sac tumor (YST). Initially, the patient presented with abnormal high signals in the right basal ganglia on MRI, misdiagnosed as a cavernous hemangioma. However, within 2 years, the condition rapidly progressed into a large, hypervascular solid neoplasm leading to a basal ganglia hemorrhage. Comprehensive evaluation of clinical symptoms, imaging, surgical findings, serology, histopathology, and genetic analysis confirmed the diagnosis of a yolk sac tumor. The patient underwent prompt surgical resection followed by radiotherapy and chemotherapy. Six months post-treatment, his condition remains stable, with no recurrence. Notably, early MRI revealed Wallerian degeneration in the brainstem suggesting that benign-appearing basal ganglia lesions may sometimes result from malignant infiltration by germ cell tumors or other cancers. To prevent misdiagnosis and ensure timely treatment, a stereotactic biopsy is recommended. We hope this case provides a valuable reference for diagnosing and treating YSTs and contributes to ongoing research aimed at improving patient survival.

Tumour stemness and poor clinical outcomes in haemochromatosis patients with hepatocellular carcinoma

AIMS

Patients with haemochromatosis (HFE) are known to have an increased risk of developing hepatocellular carcinoma (HCC). Available data are conflicting on whether such patients have poorer prognosis, and there is lack of data regarding the biology of HFE-HCC. We compared the course of HFE-HCC with a matched non-HFE-HCC control group and examined tumour characteristics using immunohistochemistry.

METHODS

In this tertiary care-based retrospective analysis, 12 patients with HFE and 34 patients with alcohol/non-alcoholic steatohepatitis who underwent initially successful curative HCC therapy with ablation or resection were identified from our registry. Time to tumour progression was compared. Resected liver tissue from a separate cohort of 11 matched patients with HFE-HCC and without HFE-HCC was assessed for the expression of progenitor and epithelial-mesenchymal transition markers using immunohistochemistry.

RESULTS

The median follow-up was 24.39 and 24.28 months for patients with HFE-HCC and those without HFE-HCC, respectively (p>0.05). The mean time to progression was shorter in the HFE group compared with the non-HFE group (12.87 months vs 17.78 months; HR 3.322, p<0.05). Patients with HFE-HCC also progressed to more advanced disease by the end of follow-up (p<0.05). Immunohistochemical analysis of matched HFE-HCC and non-HFE-HCC explants demonstrated increased expression of the cancer stem cell markers EpCAM (epithelial cell adhesion molecule) and EpCAM/SALL4 (spalt-like transcription factor 4) coexpression in HFE-HCC specimens (p<0.05). There was a high frequency of combined tumour subtypes within the HFE cohort.

CONCLUSIONS

This study demonstrates that the clinical course of patients with HFE-HCC is more aggressive and provides the first data indicating that their tumours have increased expression of progenitor markers. These findings suggest patients with HFE-HCC may need to be considered for transplant at an earlier stage.

Higher expression of SALL4-A isoform is correlated with worse outcomes and progression of the disease in subtype of testicular germ cell tumours

BACKGROUND

The transcription factor SALL4 is associated with embryonic pluripotency and has proposed as a novel immunohistochemistry (IHC) marker for diagnosing germ cell tumours. SALL4 comprises three isoforms, and SALL4-A being the full-length isoform. Studying its isoforms could revolutionize testicular cancer prognosis and subtype differentiation.

METHODS

The expression and clinical significance of isoform 'A' of SALL4 was evaluated in 124 testicular germ cell tumours (TGCTs) subtypes, adjacent 67 normal tissues and 22 benign tumours, using immunohistochemistry on tissue microarrays (TMA).

RESULTS

A statistically significant higher expression of nuclear and cytoplasmic SALL4-A was detected in TGCTs histological subtypes and benign tumours compared to the normal tissues. Seminoma and yolk sac tumours had the highest nuclear and cytoplasmic expression of SALL4-A. A significant correlation was detected between the higher nuclear expression of SALL4-A and increased pT stages (P = 0.026) in seminomas. Whereas in embryonal carcinomas, cytoplasmic expression of SALL4-A was associated with the tumour recurrence (P = 0.04) and invasion of the epididymis (P = 0.011).

CONCLUSIONS

SALL4-A isoform expression in the cytoplasm and nucleus of TGCTs may be associated with histological differentiation. In the seminoma subtype of TGCTs, higher expression of SALL4-A may be used as a predictive indicator of poorer outcomes and prognosis.

New insights on testicular cancer prevalence with novel diagnostic biomarkers and therapeutic approaches

BACKGROUND

Testicular cancer (TC), comprising merely 1% of male neoplasms, holds the distinction of being the most commonly encountered neoplasm among young males.

RECENT FINDINGS

Most cases of testicular neoplasms can be classified into two main groups, namely germ cell tumors representing approximately 95% of the cases, and sex cord-stromal tumors accounting for about 5% of the cases. Moreover, its prevalence is on the rise across the globe. TC is a neoplastic condition characterized by a favorable prognosis. The advent of cisplatin-based chemotherapeutic agents in the latter part of the 1970s has led to a significant enhancement in the 5-year survival rate, which presently surpasses 95%. Given that TC is commonly detected before reaching the age of 40, it can be anticipated that these individuals will enjoy an additional 40-50 years of life following successful treatment. The potential causes of TC are multifactorial and related to different pathologies. Accurate identification is imperative to guarantee the utmost efficacious and suitable therapy. To a certain degree, this can be accomplished through the utilization of blood examinations for neoplastic indicators; nonetheless, an unequivocal diagnosis necessitates an evaluation of the histological composition of a specimen via a pathologist.

CONCLUSION

TC is multifactorial and has various pathologies, therefore this review aimed to revise the prenatal and postnatal causes as well as novel diagnostic biomarkers and the therapeutic strategies of TC.

Primary Pediatric Yolk Sac Tumor of Liver With Lung Metastasis: An Unusual Presentation With Diagnosis Aided by LIN28 Immunohistochemistry

Yolk sac tumor is a malignant germ cell tumor, which typically occurs in the gonads with elevated serum alpha-fetoprotein (AFP). Among extragonadal sites, the liver is an uncommon location for primary pediatric yolk sac tumors. Other common hepatic tumors in this age group presenting with elevated serum AFP like hepatoblastoma and hepatocellular carcinoma must be differentiated from yolk sac tumors for initiating appropriate treatment and accurate prognostication. Lung metastasis with refractoriness to chemotherapy is an extraordinary presentation that has never been documented in the literature. We report our experience with a 2-year-old female child initially misdiagnosed as hepatoblastoma. It was found that LIN28 positivity by immunohistochemistry aided in confirmation of the histopathological diagnosis of primary yolk sac tumor of the liver.

Mixed Germ Cell Tumor with a Yolk Sac Tumor Component in the Medulla Oblongata of a 50-year-old Patient: A Case Report and Literature Review

Yolk sac tumor (YST) is a rare primary brain tumor that occurs almost exclusively in patients under 30 years old. Intracranial germ cell tumors are most frequently located in the pineal and suprasellar region. Medulla oblongata YSTs are particularly rare. Extragonadal YSTs may be difficult to diagnose because of their characteristics, such as the rarity and variety of growth patterns. Furthermore, they are known to have a very poor prognosis. We herein report a case of YST of the medulla oblongata in a 50-year-old woman. She was followed up for 18 months without any tumor recurrence.

An update on diagnostic tissue-based biomarkers in testicular tumors

Testicular cancer is rare overall but comprises the most common solid malignancy diagnosed in young men aged ∼20-40 years. Most testicular neoplasms generally fall into 2 broad categories: germ cell tumors (GCTs; ∼95%) and sex cord-stromal tumors (SCSTs ∼5%). Given the relative rarity of these tumors, diagnostic biomarkers are highly relevant for their diagnosis. Over the past several decades, diagnostic biomarkers have improved dramatically through targeted immunohistochemical and molecular characterization. Despite these recent advances, most markers are not perfectly sensitive or entirely specific. Therefore, they need to be used in combination and interpreted in context. In this review, we summarize tissue-based biomarkers relevant to the pathologist, with a focus on practical diagnostic issues that relate to testicular GCT and SCST.

Postoperative recurrence of mixed extragonadal germ cell tumor in the right shoulder: a case report

BACKGROUND

Extragonadal germ cell tumours (EGGCTs) originated in Shoulder are extremely rare, with 1 case described in the literature. We report a case of a patient with a primary Right Shoulder mixed EGGCT.

CASE PRESENTATION

A 36-year-old male patient was hospitalized for 6 months due to progressive right shoulder swelling accompanied by pain. Subsequently, the right shoulder tumor was removed entirely. Gross pathological examination showed that the size of the tumor mass was about 14 × 10 × 6 cm.Mutations were observed in ENPEP (4q25), ZCCHC11, RREB1 (6p24.3), CKAP4 (12q23.3), and other genes were detected by whole exome sequencing. Histology revealed a mixed EGGCT of the Right Shoulder with immature teratoma and yolk sac tumour. The patient went through 6 cycles of chemotherapy. After 7 months of follow-up, the patient is recurrence.

CONCLUSION

The primary MEGCT of the shoulder is an extremely rare condition. However, the recurrence and metastasis rates are high. Therefore, further research is necessary to determine this rare disease's genetic and clinical characteristics to develop an effective treatment plan.

Relapsed and refractory yolk sac tumor of the peritoneum (mesentery): A case report and literature review

Background

Extragonadal yolk sac tumor (YST) of peritoneum is a rare malignancy.

Case Description

A 37-year-old Chinese woman was admitted to hospital with a 3-month abdominal pain 4 years ago. Alpha-fetoprotein was 228,499.0 ng/mL. Computed tomography scan revealed a massive mass in the left lower abdomen. Exploratory laparotomy exposed a huge mesenteric mass. Then, mesenteric tumor resection, partial sigmoidectomy, and single-lumen fistula of sigmoid colon were performed. Postoperative pathologic diagnosis reported a stage IV mesenteric YST. After surgery, the patient received 6 courses of BEP (bleomycin, etoposide, and cisplatin) chemotherapy. Seven months later, the patient underwent stoma reversion of sigmoid colon and received another 2 courses of BEP chemotherapy. Three months after the last chemotherapy, liver metastases were diagnosed. She subsequently underwent 3 surgeries, radiotherapy for liver metastases, and multiple tiers of palliative chemotherapies, including TP (docetaxel and carboplatin), VIP (ifosfamide, cisplatin, and etoposide), TIP (paclitaxel, ifosfamide, and cisplatin), and so on. After the third surgery (left hepatic lesion resection and right iliac lymph node resection), she received 4 cyclic chemotherapies of BEP´ (boanmycin, etoposide, and cisplatin) without pulmonary toxic side effects.

Conclusion

Postoperative histopathology and immunohistochemistry are gold standards for the diagnosis of peritoneal YST. The standard first-line treatment is surgery plus BEP chemotherapy. Second-line therapy regimens and above, including VIP and TIP, improve the prognosis of recurrent germ cell tumors. This relapsed and refractory patient with peritoneal YST benefits from the secondary BEP´ chemotherapy.

Yolk Sac Tumor of the Ovary: A Report of 150 Cases and Review of the Literature

One hundred fifty yolk sac tumors (YSTs) of the ovary in patients from 1 to 61 (mean: 21.5) years of age are described; 75% of the patients were in the second and third decades and only 1 was above 50 years of age. The clinical manifestations were typically related to a fast-growing adnexal mass; endocrine manifestations (hirsutism) were present in only 2 cases. The tumors were all unilateral and 70% were ≥15 cm; an associated dermoid cyst was present in 20 cases. The tumors were solid and cystic in 57% of the cases, 25% were multicystic, and 18% uniformly solid. The solid tissue was typically tan to pink or yellow and often friable with hemorrhage and necrosis; smaller solid neoplasms were sometime uniformly yellow. The most common histologic pattern was reticular composed of an irregular meshwork of spaces that was conspicuous in 68% of the neoplasms but present to at least a minor degree in all of them. That appearance almost always merged with small to large cysts that were prominent in about 40% of tumors. In 25% of the tumors, cysts sometimes associated with a cellular stroma (the polyvesicular pattern), were present but conspicuous in only half these cases. One third of the tumors had a labyrinthine pattern, 22% glands, and 6% a festoon pattern. Papillae with a central blood vessel (Schiller-Duval bodies) were seen in one-third of the tumors but were numerous in only 5% of them. Nonspecific appearing papillae were seen in 10% of the tumors. A solid growth of cells with pale cytoplasm was seen in one-third of the tumors but was conspicuous in only half of that subset. The solid appearance was typically reminiscent of that of dysgerminoma, but lacked the septa and lymphocytic infiltrate of that neoplasm. Nine tumors had a component of cells with scant cytoplasm resulting in a blastema-like appearance and 3 had cells with abundant clear cytoplasm. Cords and clusters of cells were common but did not dominate the microscopic appearance. The stroma typically had a nonspecific collagenous to edematous appearance. Stromal luteinization was seen in 12 tumors; in 5 this was likely due to the patient being pregnant. Two tumors had minor foci of cells that resembled hepatocytes. Hyaline bodies were seen in most of the tumors and were often conspicuous. The neoplastic cells typically had modest amounts of lightly staining cytoplasm and only mild nuclear pleomorphism. Cells lining cysts were often flattened sometimes resulting in a deceptively innocuous appearance. Many of the tumors (mostly consultation cases), caused diagnostic difficulty; tumors in the differential diagnosis included clear cell carcinoma, embryonal carcinoma, Sertoli-Leydig cell tumor, and juvenile granulosa cell tumor. The patient age and marked elevation of the serum alpha-fetoprotein level (if measured) is helpful in many of these considerations. The overtly malignant gross appearance of most YSTs contrasts with certain other tumors in the differential and the association of some YSTs with dermoid cyst and many clear cell carcinomas with endometriosis may be helpful. The vast majority of ovarian YSTs are dominated microscopically by merging of reticular and cystic patterns which, although focally mimicked by other neoplasms, are in general characteristic, and distinctive features of other neoplasms are absent. Immunohistochemistry, particularly for alpha-fetoprotein and glypican 3, and lack of staining for various markers of other neoplasms is helpful but overlap exists and these results must be considered in the context of the overall clinical, gross, and microscopic features. YSTs dominated by hepatoid and glandular features are rare and their categorization as YSTs should be done cautiously if thoroughly sampled tumors show no evidence of classic features of YST emphasized herein and first elaborated by the Danish investigator Gunnar Teilum whose seminal observations have stood the test of time.

Pattern of placental alkaline phosphatase (PLAP) expression in human tumors: a tissue microarray study on 12,381 tumors

Placental alkaline phosphatase (PLAP) is commonly expressed at high levels in testicular germ cell tumors. PLAP immunohistochemistry (IHC) is thus often used to confirm this diagnosis, especially in cases of putative metastasis. However, other tumors can also express PLAP. To comprehensively determine PLAP expression in normal and tumor tissue, a tissue microarray containing 16,166 samples from 131 different tumor types and subtypes as well as 608 samples from 76 different normal tissue types was analyzed by IHC. Moderate to strong PLAP positivity was found in 27 (21%) of 131 different tumor types including seminoma (96%), embryonal carcinoma (85%), and yolk sac tumors of the testis (56%); endometrioid carcinoma of the endometrium (28%) and the ovary (20%); gastric adenocarcinoma (22%); serous carcinoma (not otherwise specified) of the ovary (17%) and the uterus (11%); adenocarcinoma of the ampulla of Vater (15%); carcinosarcoma of the ovary (11%) and the uterus (8%); esophageal adenocarcinoma (10%); invasive urothelial carcinoma (4%); cholangiocarcinoma (2%); and adenocarcinoma of the lung (1%). Low‐level PLAP immunostaining, often involving only a small fraction of tumor cells, was seen in 21 additional tumor entities. The clinical significance of PLAP expression may vary between tumor types as high PLAP expression was linked to advanced pathological tumor stage (p = 0.0086), nodal metastasis (p = 0.0085), and lymphatic (p = 0.0007) and blood vessel invasion (p = 0.0222) in colorectal cancer, but to low pathological tumor stage in endometrial cancer (p = 0.0043). In conclusion, our data identify several tumor entities that can show PLAP expression at comparable levels to testicular germ cell tumors. These tumor entities need to be considered in cases of PLAP‐positive metastasis. Low‐level PLAP expression can be found in various other tumor entities and should generally not be viewed as a strong argument for germ cell neoplasia.

Identification of Clinical Relevant Molecular Subtypes of Pheochromocytoma

Pheochromocytoma (PCC) is a rare neuroendocrine tumor of the adrenal gland with a high rate of mortality if diagnosed at a late stage. Common symptoms of pheochromocytoma include headache, anxiety, palpitation, and diaphoresis. Different treatments are under observation for PCC but there is still no effective treatment option. Recently, the gene expression profiling of various tumors has provided new subtype-specific options for targeted therapies. In this study, using data sets from TCGA and the GSE19422 cohorts, we identified two distinct PCC subtypes with distinct gene expression patterns. Genes enriched in Subtype I PCCs were involved in the dopaminergic synapse, nicotine addiction, and long-term depression pathways, while genes enriched in subtype II PCCs were involved in protein digestion and absorption, vascular smooth muscle contraction, and ECM receptor interaction pathways. We further identified subtype specific genes such as ALK, IGF1R, RET, and RSPO2 for subtype I and EGFR, ESR1, and SMO for subtype II, the overexpression of which led to cell invasion and tumorigenesis. These genes identified in the present research may serve as potential subtype-specific therapeutic targets to understand the underlying mechanisms of tumorigenesis. Our findings may further guide towards the development of targeted therapies and potential molecular biomarkers against PCC.

Pure yolk sac tumor of sacrococcygeal region

The sacrococcygeal region is the most common site for the extragonadal germ cell tumors comprising seminomatous and non-seminomatous tumors. Seminomatous tumors are seminomas, and non-seminomatous tumors comprise mainly teratoma (mature and immature), yolk sac tumor (YST), embryonal carcinoma (EC), and choriocarcinoma. These tumors occur in newborns, infants, and adolescents. Other common sites for extragonadal germ cell tumors are the brain and mediastinum, although they may occur anywhere in the body. These tumors may occur in mixed as well as pure form. So, sectioning from different areas should be done before labeling them as pure germ cell tumors. YST, in its pure form, is rare and therefore should not be missed as it is chemosensitive. The patient should be thoroughly assessed clinically. Imaging also becomes necessary while evaluating swelling in the sacrococcygeal region and can aid in differentials. When the clinical and imaging suspicion of either Sacrococcygeal teratoma or other germ cell tumor is high, serum biomarkers as alfa-fetoprotein should be requested. The serum levels are necessary and should be done preoperatively, postoperatively, and during the course of chemotherapy as follow-up. However, the final diagnosis rests on the histopathological diagnosis. We report one such case of pure YST in the sacrococcygeal region in a 9-month-old female child. The imaging suggested sacrococcygeal teratoma type 4, and high alfa-fetoprotein levels were determined postoperatively.

Female Germ Cell Development, Functioning and Associated Adversities under Unfavorable Circumstances

In the present era, infertility is one of the major issues which restricts many couples to have their own children. Infertility is the inability to achieve a clinical pregnancy after regular unprotected sexual intercourse for the period of one year or more. Various factors including defective male or female germ cell development, unhealthy and improper lifestyles, diseases like cancer and associated chemo-or-radiation therapies, congenital disorders, etc., may be responsible for infertility. Therefore, it is highly important to understand the basic concepts of germ cell development including primordial germ cell (PGC) formation, specification, migration, entry to genital ridges and their molecular mechanisms, activated pathways, paracrine and autocrine signaling, along with possible alteration which can hamper germ cell development and can cause adversities like cancer progression and infertility. Knowing all these aspects in a proper way can be very much helpful in improving our understanding about gametogenesis and finding possible ways to cure related disorders. Here in this review, various aspects of gametogenesis especially female gametes and relevant factors causing functional impairment have been thoroughly discussed.

Recombinant immunotoxin targeting GPC3 is cytotoxic to H446 small cell lung cancer cells

Glypican-3 (GPC3) is a cell membrane glycoprotein that regulates cell growth and proliferation. Aberrant expression or distribution of GPC3 underlies developmental abnormalities and the development of solid tumours. The strongest evidence for the participation of GPC3 in carcinogenesis stems from studies on hepatocellular carcinoma and lung squamous cell carcinoma. To the best of our knowledge, the role of the GPC3 protein and its potential therapeutic application have never been studied in small cell lung carcinoma (SCLC), despite the known involvement of associated pathways and the high mortality caused by this disease. Therefore, the aim of the present study was to examine GPC3 targeting for SCLC immunotherapy. An immunotoxin carrying an anti-GPC3 antibody (hGC33) and Pseudomonas aeruginosa exotoxin A 38 (PE38) was generated. This hGC33-PE38 protein was overexpressed in E. coli and purified. ADP-ribosylation activity was tested in vitro against eukaryotic translation elongation factor 2. Cell internalisation ability was confirmed by confocal microscopy. Cytotoxicity was analysed by treating liver cancer (HepG2, SNU-398 and SNU-449) and lung cancer (NCI-H510A, NCI-H446, A549 and SK-MES1) cell lines with hGC33-PE38 and estimating viable cells number. A BrdU assay was employed to verify anti-proliferative activity of hGC33-PE38 on treated cells. Fluorescence-activated cell sorting was used for the detection of cell membrane-bound GPC3. The hGC33-PE38 immunotoxin displayed enzymatic activity comparable to native PE38. The protein was efficiently internalised by GPC3-positive cells. Moreover, hGC33-PE38 was cytotoxic to HepG2 cells but had no effect on known GPC3-negative cell lines. The H446 cells were sensitive to hGC33-PE38 (IC₅₀, 70.6±4.6 ng/ml), whereas H510A cells were resistant. Cell surface-bound GPC3 was abundant on the membranes of H446 cells, but absent on H510A. Altogether, the present findings suggested that GPC3 could be considered as a potential therapeutic target for SCLC immunotherapy.

Napabucasin overcomes cisplatin resistance in ovarian germ cell tumor-derived cell line by inhibiting cancer stemness

Background

Cisplatin resistance of ovarian yolk sac tumors (oYST) is a clinical challenge due to dismal patient prognosis, even though the disease is extremely rare. We investigated potential association between cisplatin resistance and cancer stem cell (CSC) markers in chemoresistant oYST cells and targeting strategies to overcome resistance in oYST.

Methods

Chemoresistant cells were derived from chemosensitive human oYST cells by cultivation in cisplatin in vitro. Derivative cells were characterized by chemoresistance, functional assays, flow cytometry, gene expression and protein arrays focused on CSC markers. RNAseq, methylation and microRNA profiling were performed. Quail chorioallantoic membranes (CAM) with implanted oYST cells were used to analyze the micro-tumor extent and interconnection with the CAM. Tumorigenicity in vivo was determined on immunodeficient mouse model. Chemoresistant cells were treated by inhibitors intefering with the CSC properties to examine the chemosensitization to cisplatin.

Results

Long-term cisplatin exposure resulted in seven-fold higher IC₅₀ value in resistant cells, cross-resistance to oxaliplatin and carboplatin, and increased migratory capacity, invasiveness and tumorigenicity, associated with hypomethylation of differentially methylated genes/promotors. Resistant cells exhibited increased expression of prominin-1 (CD133), ATP binding cassette subfamily G member 2 (ABCG2), aldehyde dehydrogenase 3 isoform A1 (ALDH3A1), correlating with reduced gene and promoter methylation, as well as increased expression of ALDH1A3 and higher overall ALDH enzymatic activity, rendering them cross-resistant to DEAB, disulfiram and napabucasin. Salinomycin and tunicamycin were significantly more toxic to resistant cells. Pretreatment with napabucasin resensitized the cells to cisplatin and reduced their tumorigenicity in vivo.

Conclusions

The novel chemoresistant cells represent unique model of refractory oYST. CSC markers are associated with cisplatin resistance being possible targets in chemorefractory oYST.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

Hepatoid carcinoma of the ovary - A case report and literature review

We present the case of a 27-year old female with an ovarian tumor and alpha-fetoprotein (AFP) of 1210 ng/m, a right salpingo-oophorectomy was performed and had conservative complementary staging by gynecologic oncologists. The histopathological report was primary hepatoid carcinoma of the ovary (HCO), clinical stage IA, complementary treatment was adjuvant chemotherapy with BEP and remains clinical, imaging and biochemically disease free in three years follow up.

Endometrial tumors with yolk sac tumor-like morphologic patterns or immunophenotypes: an expanded appraisal

Uterine yolk sac tumors have gained increased recognition in recent years. The current study is a multi-faceted examination of yolk sac tumor-like phenotypes in endometrial tumors, based on an analysis of 3 groups of uterine tumors: Group 1: 9 endometrial tumors that had been classified as yolk sac tumor, or as having a yolk sac tumor component, were assessed with a 35-marker immunohistochemical panel, with the goal of defining their immunophenotypic spectrum; Group 2, comprised of 70 endometrial carcinomas of various histotypes, were analyzed for their expression of SALL4, Glypican-3, and AFP, to assess the specificity of these markers for yolk sac tumors relative to endometrial carcinomas; Group 3, comprised of 626 archived cases of endometrial carcinoma/carcinosarcoma, reviewed to define the frequency of yolk sac tumor-like morphology therein. Yolk sac tumor areas in the Group 1 cases were consistently immunoreactive for SALL4 and Glypican-3; variably positive for AFP (89%), Villin (89%), PLAP (78%), 34βE12 (67%), CAM 5.2 (62.5%), EMA (56%), CD117 (50%), p16 (50%), CDX2 (44%), p53 (44% aberrant), MOC31 (37.5%), CK7 (33%), GATA3 (33%), CK5 (25%), and PAX8 (11%); and were negative for CD30, Napsin A, OCT4, estrogen, androgen, and progesterone receptors. 29 (41%) of the 70 group-2 cases expressed at least one of the 3 markers, and 96% of the positive cases was a high-grade histotype. Glypican-3, SALL4, and AFP were positive in 30, 20, and 2.8% of group-2 cases respectively; however, co-expression of any 2, or all 3 markers was uncommon (<9 and 1.4% of cases respectively). Potential yolk sac tumor-like morphology was identified in 5 (0.8%) of 626 group-3 cases, and three were ultimately deemed to be true yolk sac tumor phenotypes based on their morphologic and immunophenotypic similarity to the group 1 cases. These findings highlight the broad immunophenotypic spectrum of uterine yolk sac tumors, the potential pitfalls associated with using immunophenotypes alone to define yolk sac tumor differentiation in endometrial carcinoma, and the utility and limitations of morphologic assessment to identify yolk sac tumors at this site.

Extragonadal germ cell tumors: Not just a matter of location. A review about clinical, molecular and pathological features

Extragonadal germ cell tumors (EGGCTs) are uncommon neoplasms, which arise in anatomical locations other than gonads. The pathogenesis of these neoplasms is still poorly understood and it is a matter of debate if they really represent extragondal primary neoplasms or rather extragondal metastasis from occult gonadal neoplasms. The actual observations suggest that EGGCTs represent a unique entity, so their biology and behavior are substantially different from gonadal counterparts. The diagnosis of EGGCTs is often challenging, and differential diagnosis is particularly wide. Nevertheless, a correct diagnosis is essential for the correct management of the patient. We summarize the state of art about EGGCTs, with particular emphasis on diagnosis and prognosis.

Practical Application of Lineage-Specific Immunohistochemistry Markers: Transcription Factors (Sometimes) Behaving Badly

CONTEXT.—

Transcription factors (TFs) are proteins that regulate gene expression and control RNA transcription from DNA. Lineage-specific TFs have increasingly been used by pathologists to determine tumor lineage, especially in the setting of metastatic tumors of unknown primary, among other uses. With experience gathered from its daily application and increasing pitfalls reported from immunohistochemical studies, these often-touted highly specific TFs are not as reliable as once thought.

OBJECTIVES.—

To summarize the established roles of many of the commonly used TFs in clinical practice and to discuss known and potential sources for error (eg, false-positivity from cross-reactivity, aberrant, and overlap "lineage-specific" expression) in their application and interpretation.

DATA SOURCES.—

Literature review and the authors' personal practice experience were used. Several examples selected from the University Health Network (Toronto, Ontario, Canada) are illustrated.

CONCLUSIONS.—

The application of TF diagnostic immunohistochemistry has enabled pathologists to better assess the lineage/origin of primary and metastatic tumors. However, the awareness of potential pitfalls is essential to avoid misdiagnosis.

Multidisciplinary team for the diagnosis and treatment of 2 cases of primary intestinal yolk sac tumor

Extragonadal primary yolk sac tumor of the intestinal tract origin is exceedingly rare. Through a multiple disciplinary team, the diagnosis and treatment of primary intestinal yolk sac tumor were further defined. We report 2 such cases with detailed histologic and immunohistochemical analysis. The two patients were a 7-year-old girl and a 29-year-old woman. Both of them preoperatively had an elevated serum alpha fetoprotein (AFP) level (≥ 1,210 ng/mL). The tumors are located in the intestine and imaging examination indicated the rectum as the primary site. Grossly the mass was grey-white and crisp texture. Microscopic examination featured reticular, microcystic, macrocystic, papillary, solid, and some glandular patterns. Immunohistochemically, tumor cells of both cases were positive for SALL4, AFP, pan-cytokeratin (AE1/AE3), and glypican-3. Simultaneously, a stain for EMA, OCT4, CD30, HCG, vimentin and CK20 were negative in all 2 neoplasms. The features of morphology, immunohistochemistry, laboratory examinations and imaging studies consist of the diagnosis of primary yolk sac tumor of the intestine.

Expression of RNA-binding protein LIN28 in classic gastric hepatoid carcinomas, gastric fetal type gastrointestinal adenocarcinomas, and hepatocellular carcinomas: An immunohistochemical study with comparison to SALL4, alpha-fetoprotein, glypican-3, and Hep Par1

INTRODUCTION

Gastric hepatoid carcinomas (GHCs) include type I (classic) and type II (fetal type gastrointestinal adenocarcinoma). The classic type shows overlapping morphologic features with those of hepatocellular carcinoma (HCC). The aim of this study is to investigate expression of LIN28 in GHCs and explore its utility to distinguish classic GHC from HCC.

METHODS

We investigated immunohistochemical expression of LIN28 in 93 primary GHCs (47 type I, 46 type II) and 60 HCCs with comparison to SALL4, AFP, glypican-3, Hep Par1, p-CEA and CK7. We also stained LIN28 and SALL4 in 52 conventional gastric adenocarcinomas to assess their specificity in gastric carcinomas.

RESULTS

Classic GHCs and fetal type gastrointestinal adenocarcinomas showed positive LIN28 in 21/47 (45%) and 10/46 (22%), SALL4 in 41/47 (87%) and 36/46 (78%), AFP in 30/46 (65%) and 33/46 (72%), glypican-3 in 31/41 (76%) and 24/38 (63%), Hep Par1 in 27/41 (66%) and 28/37 (76%), and CK7 in 15/40 (38%) and 25/38 (66%), respectively. p-CEA staining was seen in 19/44 (43%) classic GHCs. Among HCCs, LIN28, SALL4, AFP, glypican-3, Hep Par1, p-CEA and CK7 was seen in 1/60 (2%), 0/60 (0%), 6/30 (20%), 23/30 (77%), 29/30 (97%), 28/30 (93%) and 21/30 (70%) cases, respectively. LIN28 and SALL4 staining was seen in 2/52 (4%) and 14/52 (27%) gastric conventional adenocarcinomas, respectively. The sensitivity and specificity of distinguishing classic GHCs from HCCs was 45% and 98% for LIN28, 87% and 100% for SALL4, 65% and 80% for AFP, 76% and 30% for glypican-3, 66% and 3% for Hep Par1, 43% and 7% for p-CEA, and 38% and 30% for CK7, respectively. Combining LIN28 and SALL4 increased the sensitivity to 96% with 98% specificity to distinguish classic GHCs from HCCs.

CONCLUSIONS

LIN28 is a very specific marker (98% specificity) for distinguishing classic GHCs from HCCs though it is not as sensitive as SALL4. AFP, glypican-3, Hep Par1 and p-CEA are not useful in distinguishing classic GHCs from HCCs. Combining LIN28 and SALL4 increased the sensitivity to distinguish classic PHCs from HCCs.

Glypican 3 Overexpression across a Broad Spectrum of Tumor Types Discovered with Functional Genomic mRNA Profiling of a Large Cancer Database

Glypican 3 (GPC3), a membrane-bound heparan sulfate proteoglycan, is overexpressed in approximately 70% to 80% of hepatocellular carcinomas, but is not expressed commonly in healthy tissues. This raised interest in GPC3 as a drug target and several GPC3-targeting drugs are in clinical development. We therefore predicted GPC3 protein overexpression across tumors and validated these predictions. Functional genomic mRNA profiling was applied to the expression profiles of 18,055 patient-derived tumor samples to predict GPC3 overexpression at the protein level in 60 tumor types and subtypes using healthy tissues as reference. For validation, predictions were compared with immunohistochemical (IHC) staining of a breast cancer tissue microarray and literature data reporting IHC GPC3 overexpression in various solid, hematologic, and pediatric tumors. The percentage of samples with predicted GPC3 overexpression was 77% for hepatocellular carcinomas (n = 364), 45% for squamous cell lung cancers (n = 405), and 19% for head and neck squamous cell cancers (n = 344). Breast cancer tissue microarray analysis showed GPC3 expression ranged from 12% to 17% in subgroups based on estrogen receptor and human epidermal growth factor receptor 2 status. In 28 of 34 tumor types for which functional genomic mRNA data could be compared with IHC there was a relative difference of ≤10%. This study provides a data-driven prioritization of tumor types and subtypes for future research with GPC3-targeting therapies.

The International Stem Cell Initiative, Allison TF, Andrews PW, Avior Y, Barbaric I, Benvenisty N, Bock C, Brehm J, Brüstle O, Damjanov I, Elefanty A, Felkner D, Gokhale PJ, Halbritter F, Healy LE, Hu TX, Knowles BB, Loring JF, Ludwig TE, Mayberry R, Micallef S, Mohamed JS, Müller FJ, Mummery CL, Nakatsuji N, Ng ES, Oh SKW, O’Shea O, Pera MF, Reubinoff B, Robson P, Rossant J, Schuldt BM, Solter D, Sourris K, Stacey G, Stanley EG, Suemori H, Takahashi K, Yamanaka S. Assessment of established techniques to determine developmental and malignant potential of human pluripotent stem cells

The International Stem Cell Initiative compared several commonly used approaches to assess human pluripotent stem cells (PSC). PluriTest predicts pluripotency through bioinformatic analysis of the transcriptomes of undifferentiated cells, whereas, embryoid body (EB) formation in vitro and teratoma formation in vivo provide direct tests of differentiation. Here we report that EB assays, analyzed after differentiation under neutral conditions and under conditions promoting differentiation to ectoderm, mesoderm, or endoderm lineages, are sufficient to assess the differentiation potential of PSCs. However, teratoma analysis by histologic examination and by TeratoScore, which estimates differential gene expression in each tumor, not only measures differentiation but also allows insight into a PSC's malignant potential. Each of the assays can be used to predict pluripotent differentiation potential but, at this stage of assay development, only the teratoma assay provides an assessment of pluripotency and malignant potential, which are both relevant to the pre-clinical safety assessment of PSCs.

Oncofetal gene SALL4 reactivation by hepatitis B virus counteracts miR-200c in PD-L1-induced T cell exhaustion

A chronic viral or tumor microenvironment can push T cells to exhaustion by promoting coinhibitory ligand expression. However, how host factors control coinhibitory ligand expression and whether viral infection breaks this control during tumor progress is unknown. Here we show a close negative correlation between SALL4 or PD-L1 and miR-200c in tumors from 98 patients with HBV-related hepatocellular carcinoma. SALL4 or PD-L1 expression correlates negatively with miR-200c expression, and patients with lower levels of SALL4 or PD-L1 and higher miR-200c survive longer. Moreover, over-expression of miR-200c antagonizes HBV-mediated PD-L1 expression by targeting 3'-UTR of CD274 (encoding PD-L1) directly, and reverses antiviral CD8⁺ T cell exhaustion. MiR-200c transcription is inhibited by oncofetal protein SALL4, which is re-expressed through HBV-induced STAT3 activation in adulthood. We propose that an HBV-pSTAT3-SALL4-miR-200c axis regulates PD-L1. Therapeutic strategies to influence this axis might reverse virus-induced immune exhaustion.

Right Ventricular Heart Failure from a Cardiac Yolk Sac Tumor

Patient: Male, 46

Final Diagnosis: Yolk Sac tumor

Symptoms: Shortness of breath

Medication: —

Clinical Procedure: Cardiac MRI • tumor resection

Specialty: Cardiology

Yolk Sac Tumor in Extragonadal Pelvic Sites: Still a Diagnostic Challenge

We present the clinicopathologic features of 15 cases of extragonadal yolk sac tumor (EGYST) detected in female patients and reviewed at our institution from 1988 to 2016. We recorded: patient age, clinical presentation, tumor location, FIGO stage (where applicable), histologic patterns including presence/absence of Schiller-Duval bodies, other germ cell or somatic components, immunoperoxidase results, treatment, and outcome. Patients' ages ranged from 17 to 87 (median, 62) years and presentation included: abnormal uterine bleeding, 12; hematuria, 1; labial mass, 1; abdominal pain, 1. Primary sites were as follows: uterus (11), vagina (1), vulva (1), bladder (1), and peritoneum (1). Seven patients presented at FIGO stage III or IV. The following histologic patterns were observed: microcystic/reticular (7), glandular (8), solid (8), papillary (5), and hepatoid (1). An admixture of histologic patterns was present in 10 cases. Schiller-Duval bodies were seen in only 3 (23%) cases. Eight cases (46%), all uterine primaries, had associated somatic components, and 2 (15%) had a second germ cell component. In 13/14 (93%) cases, the yolk sac tumor component was either missed or misclassified as adenocarcinoma. Immunoperoxidase studies facilitated the diagnosis in all cases as follows: SALL4, 12/12; CDX2, 10/12; α fetoprotein, 7/14; glypican-3, 9/10; cytokeratin 20, 5/9 (rare cells); cytokeratin 7, 3/12 (nondiffuse); PAX8, 2/9 (variable expression). All patients received chemotherapy and all except 1 underwent surgical resection. Follow-up from 5 to 86 months was available for 13 patients: 5 died of disease, 6 are alive with disease, and 2 have no evidence of disease. EGYST arising in the female pelvis of peri/postmenopausal patients may be associated with a somatic component and represent either somatically derived YST or YST differentiation within a somatic carcinoma. EGYST in younger patients is likely a true germ cell neoplasm, and may respond to germ cell appropriate chemotherapy. The benefit of germ cell appropriate chemotherapy in somatically derived EGYST is less clear. Awareness that the presence of glandular or microcystic patterns may lead to under-recognition or misdiagnosis of EGYST in combination with immunomarkers for germ cell and yolk sac differentiation will facilitate the diagnosis.

Unusual Presentations of Gynecologic Tumors: Extragonadal Yolk Sac Tumor of the Vulva

Extragonadal germ cell tumors are uncommon, and although they morphologically resemble their gonadal counterparts, unexpected gonadal presentation increases the potential for erroneous diagnoses. Yolk sac tumor is a malignant germ cell tumor characterized by an extraembryonic yolk sac line of differentiation, and relative to other germ cell tumors, is characterized by varied and diverse histologic patterns. When occurring outside of typical age parameters or in extragonadal locations, the histologic variability of yolk sac tumor and its tendency to mimic somatic tumors pose diagnostic challenges. Because extragonadal yolk sac tumor of the vulva is very rare, with only isolated case reports and small series in the literature, it is often not considered in the differential diagnosis. As both prognosis and management of yolk sac tumor differ significantly from those of somatic tumors, accurate diagnosis is essential. This review discusses histologic features of extragonadal yolk sac tumor, addresses somatic tumors arising in the vulva for which yolk sac tumor may be confused, and provides guidance with respect to the use of immunohistochemistry in the diagnosis of yolk sac tumor.

Knockdown of Sall4 inhibits intrahepatic cholangiocarcinoma cell migration and invasion in ICC-9810 cells

In spite of improvements in surgical technology, the resectability and curability of intrahepatic cholangiocarcinoma (ICC) are still low. Our previous study showed that the strong Sal-like protein 4 (Sall4)-positive cases had shorter overall survival compared to Sall4-negative cases, indicating an oncogenic role of Sall4 in ICC. In this study, we aimed to explore the precise mechanism of Sall4 on ICC cell invasion and metastasis. We evaluated the expression of Sall4, PTEN, and Bmi-1 in 28 cases of adjacent tissues and 175 cases of ICC tissues by using immunohistochemical staining. We found that the expression of Sall4 and Bmi-1 was significantly increased in ICC tissues compared with the adjacent tissues, while PTEN expression was reduced in ICC tissues compared with the adjacent tissues, and there was a reverse relationship between Sall4 and PTEN in ICC, whereas there was a positive correlation in Sall4 and Bmi-1 expression in ICC. In addition, overall survival analysis showed that ICC patients with low PTEN exhibited a worse prognosis than ICC patients with high PTEN, and lower Bmi-1 expression showed a better prognosis than ICC patients with high Bmi-1. By a battery of experiments in vitro, we demonstrated that Sall4 promotes ICC cell proliferation, and progression of ICC might be through PTEN/PI3K/Akt and Bmi-1/Wnt/β-catenin signaling and enhancing epithelial-mesenchymal transition process. Thus, Sall4 may be a potential target for the treatment of ICC metastasis.

SALL4 is a novel therapeutic target in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the most common and deadly disease of the biliary tree due to its poor prognosis. Sal-like protein 4 (SALL4), a stem cell marker, has been identified as a potential target for aggressive hepatocellular carcinoma (HCC). In our study, 175 ICC cases with an average age of 55 years were included, and 53% (93/175) were male. And 28 adjacent non-tumor tissues were also collected. The SALL4-positive immunoreactivity was detected in a total of 102 ICC cases (58%), whereas all 28 adjacent tissues showed negative staining. Univariate analysis, showed that the SALL4-positive ICC cases had significantly more frequent lymph nodal metastasis (P = 0.0460), vascular invasion (P < 0.0001), and nerve invasion (P < 0.0001). Furthermore, the strong SALL4-positive cases (n = 7, 5 months) had shorter overall survival, when compared to moderate SALL4-positive (n = 46, 9 months) or SALL4-negative cases (n = 73, 7 months), respectively. Our data also suggest that SALL4 may be involved in the regulation of epithelial-mesenchymal transition (EMT) in ICC. Those results for the first time indicate an oncogenic role of SALL4 in ICC. Therefore, SALL4 may serve as a promising therapeutic target for ICC.

SALL4 expression in gestational trophoblastic tumors: a useful tool to distinguish choriocarcinoma from placental site trophoblastic tumor and epithelioid trophoblastic tumor

SALL4 has important functions in embryonic stem cells. The aim of this study was to investigate SALL4 expression in gestational trophoblastic neoplasia. We hypothesized that it could help to distinguish choriocarcinoma, the presumed most primitive form of gestational trophoblastic neoplasia, from placental site trophoblastic tumor and epithelioid trophoblastic tumor, which would be more differentiated variants. This study included 31 gestational trophoblastic neoplasias: 19 choriocarcinomas, 9 placental site trophoblastic tumors, 1 epithelioid trophoblastic tumor, and 2 mixed tumors comprising a placental site trophoblastic tumor and an epithelioid trophoblastic tumor. Unlike usual markers of gestational trophoblastic neoplasia (p63, human chorionic gonadotrophin and human placental lactogen), SALL4 was expressed in 100% of choriocarcinomas and it was not detected in any placental site trophoblastic tumor and epithelioid trophoblastic tumor. However, the proportion of positive cells varied in a wide range, from 10% to 70%, reflecting the fact that SALL4 was specifically present in mononuclear cells consistent with neoplastic cytotrophoblast. So, SALL4 may be helpful in the differential diagnosis of gestational trophoblastic neoplasias.

The zinc-finger transcription factor SALL4 is frequently expressed in human cancers: association with clinical outcome in squamous cell carcinoma but not in adenocarcinoma of the esophagus

SALL4 is a transcription factor originally identified as a homeotic gene essential for organ development. Early studies suggested that SALL4 is a useful marker to identify testicular and ovarian germ cell tumors. The aim of the study was to evaluate the diagnostic potential of SALL4 immunohistochemistry. Immunohistochemical staining was performed on a tissue microarray (TMA) with 3966 samples from 94 different tumor types and on a further TMA with 492 esophagus carcinomas. SALL4 immunostaining was by far most prevalent and most intensive in testicular tumors with a positivity rate of 93.1% in seminomas, 80% in mixed germ cell tumors (embryonic carcinomas/yolk sac tumors), and 18.5% in teratomas, respectively. However, SALL4 expression is not specific to germ cell tumors. We observed SALL4 positivity in non-germ cell tumors as carcinomas of the kidney (28.9% of chromophobe, 34.4% of clear cell carcinoma), in intestinal type adenocarcinoma of the stomach (10.9%), in adenocarcinoma (10.5%) and squamous cell carcinoma (7.2%) of the esophagus, and in malignant melanoma (8.1%) and invasive urothelial bladder carcinoma (20%). SALL4 expression was not found in lymphomas, in soft tissue tumors or breast tumors. At analysis of esophagus carcinoma TMA, no significant association was seen between SALL4 expression and overall survival in adenocarcinoma. However, SALL4 expression was strongly associated with worse overall survival in squamous cell carcinoma. SALL4 expression can be found at relevant frequencies in various tumors of different primary sites. SALL4 expression in squamous cell carcinoma of the esophagus may constitute a sign of dedifferentiation leading to poor patient prognosis.

Analysis of POU5F1, c-Kit, PLAP, AP2γ and SALL4 in gonocytes of patients with cryptorchidism

Cryptorchidism is a risk factor for the development of testicular germ cell tumors (TGCTs). The most common type of TGCT in cryptorchidism is seminoma. The intratubular germ cell neoplasia unclassified (ITGCNU) is a histological pattern preceding the development of seminomas and non-seminomas. It was suggested that in patients with cryptorchidism, the gonocytes remained undifferentiated with pluripotent abilities expressing proteins like POU domain class 5 transcription factor 1 (POU5F1), tyrosine kinase receptor c-Kit, placental-like alkaline phosphatase (PLAP), the transcription factor AP2γ and sal-like protein 4 (SALL4) that confer to the gonocytes this ability and therefore make them susceptible to develop ITGCNU. The aim of the present study was to determine if the gonocytes of patients with cryptorchidism express POU5F1, c-Kit, PLAP, AP2γ and SALL4 proteins after their differentiation period. Based on this, we evaluated samples of testicular tissue from newborns to 16-year old subjects with or without cryptorchidism in search of POU5F1, c-Kit, PLAP, AP2γ and SALL4 using immunocytochemical method, the results of which were validated by RT-PCR. The results showed that control subjects witnessed a down-regulation in the expression of these five proteins in the first year of life, which eventually disappeared. On the other hand, it was determined that 21.6% (8/37) of the patients with cryptorchidism continued to express, at least, one of the proteins analyzed in this study after the second year of life. And only 5.4% (2/37) of the patients were positive to the five markers. These data sustain the proposed hypothesis that in cryptorchid patients, ITGCNU arises from gonocytes that fail in their differentiation process to spermatogonia with conservation of the proteins (POU5F1, c-Kit, PLAP, AP2γ and SALL4) that maintain pluripotency and undifferentiated characteristics and which are responsible for making the gonocytes susceptible to malignancy. However, we cannot guarantee that these patients present neoplastic transformation.

Immunohistochemistry in undifferentiated neoplasm/tumor of uncertain origin

CONTEXT

Immunohistochemistry has become an indispensable ancillary study in the identification and classification of undifferentiated neoplasms/tumors of uncertain origin. The diagnostic accuracy has significantly improved because of the continuous discoveries of tissue-specific biomarkers and the development of effective immunohistochemical panels.

OBJECTIVES

To identify and classify undifferentiated neoplasms/tumors of uncertain origin by immunohistochemistry.

DATA SOURCES

Literature review and authors' research data and personal practice experience were used.

CONCLUSIONS

To better guide therapeutic decisions and predict prognostic outcomes, it is crucial to differentiate the specific lineage of an undifferentiated neoplasm. Application of appropriate immunohistochemical panels enables the accurate classification of most undifferentiated neoplasms. Knowing the utilities and pitfalls of each tissue-specific biomarker is essential for avoiding potential diagnostic errors because an absolutely tissue-specific biomarker is exceptionally rare. We review frequently used tissue-specific biomarkers, provide effective panels, and recommend diagnostic algorithms as a standard approach to undifferentiated neoplasms.

SALL4: an emerging cancer biomarker and target

SALL4 is a transcription factor that plays essential roles in maintaining self-renewal and pluripotency of embryonic stem cells (ESCs). In fully differentiated cells, SALL4 expression is down-regulated or silenced. Accumulating evidence suggest that SALL4 expression is reactivated in cancer. Constitutive expression of SALL4 transgene readily induces acute myeloid leukemia (AML) development in mice. Gain- and loss-of-function studies reveal that SALL4 regulates proliferation, apoptosis, invasive migration, chemoresistance, and the maintenance of cancer stem cells (CSCs). SALL4 controls the expression of its downstream genes through both genetic and epigenetic mechanisms. High level of SALL4 expression is detected in cancer patients, which predicts adverse progression and poor outcome. Moreover, targeted inhibition of SALL4 has shown efficient therapeutic effects on cancer. We have summarized the recent advances in the biology of SALL4 with a focus on its role in cancer. Further study of the oncogenic functions of SALL4 and the underlying molecular mechanisms will shed light on cancer biology and provide new implications for cancer diagnostics and therapy.

Discovery and diagnostic value of a novel oncofetal protein: glypican 3

Glypican 3 is a membrane-bound heparan sulfate proteoglycan, which has recently been identified as a marker for liver cancer and germ cell malignancies. Individuals with loss-of-function mutations for the glypican 3 gene exhibit Simpson-Golabi-Behmel syndrome, a rare X-linked overgrowth disorder. Expression of glypican 3 mRNA and protein is normally silenced in most adult organs and may reappear during malignant transformation. In the past few years, immunohistochemical and molecular characteristics of glypican 3 in hepatocellular carcinoma have been elucidated. More recently, glypican 3 has been emerging as a new diagnostic marker for germ cell tumors and especially testicular and ovarian yolk sac tumors. However, in other tumors such as renal cell carcinomas, squamous cell carcinomas, and melanomas, studies disagree on the level of glypican 3 expression. Finally, there is the controversial notion of glypican 3 as a tumor suppressor gene. In this review article, we update current knowledge on glypican 3 expression in normal and neoplastic tissues, evaluate its utility as a tumor marker in clinical practice, and explore its role as a novel oncofetal protein with clinical implications. Our focus is on the diagnostic value of glypican 3 in germ cell tumors and other neoplasms in addition to hepatocellular carcinoma. In conclusion, glypican 3 has been proven to be a useful immunohistochemical marker in distinguishing yolk sac tumors, choriocarcinomas, and Wilms tumors from other malignancies histologically mimicking these primitive tumors. Clinically, we recommend that glypican 3 be used as part of a panel of markers in subtyping testicular germ cell tumors.

SALL4 immunoreactivity predicts prognosis in Western hepatocellular carcinoma patients but is a rare event: a study of 236 cases

Prognostic biomarkers that stratify patients with cancer are needed. Recent studies from Asia have implicated SALL4, a stem cell marker, as useful in identifying aggressive cases of hepatocellular carcinoma (HCC), and >50% of the cases tested had upregulation by microarray or dense immunoreactivity. Given the differences in predominant etiologic factors between the Asian and Western HCC, we sought to determine the prevalence of SALL4 immunoreactivity and its clinical relevance in Western HCC patients. We constructed tissue microarrays from 236 adult HCCs. Two cores each of tumor and nontumor tissue were included for each case. SALL4 immunohistochemistry was scored in a semiquantitative manner and the results correlated with recurrence-free and overall survival, in addition to standard demographics. Among the 236 cases, 165 (70.0%) were male. The median age was 59 years (range: 19 to 83 y). The majority (78.4%) of patients were white, followed by African American (15.7%), Asian (3.8%), Hispanic (1.7%), and Native American (0.4%). The majority of patients had hepatitis C (42.8%), followed by alcoholic liver disease and hepatitis B (both 8.9%), and nonalcoholic steatohepatitis (3.8%). SALL4 immunoreactivity was detected in a total of 3 cases (1.3%), and nonreactivity was validated on tissue sections from 73 cases. By univariate analysis, the SALL4-positive cases had significantly higher tumor grade (P=0.0251), more frequent lymphovascular invasion (P=0.0150), and shorter recurrence-free survival (7.90 vs. 57.54 mo; P=0.0115) and overall survival (7.90 vs. 64.87 mo; P=0.0018). Although SALL4 immunoreactivity in Western HCC is correlated with higher grade and poor prognosis, this is a rare event. Therefore, universal application of SALL4 as a biomarker for HCC should be performed with caution.

Sinonasal pure yolk sac tumor: a case report and literature review

Extragonadal pure yolk sac tumor of sinonasal origin is very rare. We report herein a case with sinonasal yolk sac tumor in a 1 year and 3 months old girl. The initial complaint was persistent nasal bleeding for about 2 months. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a lobulated soft tissue mass in paranasal sinus that extended to oral cavity, nasopharynx, and oropharynx. The histology showed typical features of yolk sac tumor and the positive immunohistochemical staining of SALL4 and α-fetoprotein. After tumor excision, adjuvant chemotherapy of JEB regimen was prescribed. After the follow-up for 13-months, α-fetoprotein was normal and neither tumor progression nor metastasis was found. We review the previous literature and discuss the etiology, histology, treatment, and the prognosis of the rare sinonasal yolk sac tumor.

Serum SALL4 is a novel prognosis biomarker with tumor recurrence and poor survival of patients in hepatocellular carcinoma

AIM

Sal-like protein 4 (SALL4), is reexpressed in tissues of a subgroup of HCC associated with poor prognosis. Reports of SALL4 serological levels linked to HCC patients are meager and unclear in the prognosis of this malignancy.

METHODS

Immunohistochemistry and optical microscopy protocols were used to examine the presence of SALL4 in liver tissues from the following patients: 38 HCC, 11 chronic hepatitis B virus (HBV), 13 liver cirrhosis, and 12 healthy controls. Additionally, enzyme-linked immunosorbent assay (ELISA) was used to measure the SALL4 levels in serum samples isolated from patients as follows: 127 with HCC, 27 with HBV, 24 with liver cirrhosis, and 23 normal controls.

RESULTS

Analysis of liver tissues sections from HCC patients (18 out 38; 47.4%) showed positive staining for SALL4 and its expression did no correlate with any of the clinicopathologic characteristics. HCC patients displayed higher levels (50.4%) of SALL4 protein in serum, compared with the three control groups. Moreover, SALL4 concentration reached the maximum level after one week after treatment and dropped quickly after one month. These HCC patients showing high SALL4 serum levels had poor prognosis, evidenced by both tumor recurrence and overall survival rate.

CONCLUSIONS

High SALL4 serum levels are a novel biomarker in the prognosis of HCC patients.

SALL4 expression in germ cell and non-germ cell tumors: a systematic immunohistochemical study of 3215 cases

The SALL4 transcription factor is associated with embryonic cell pluripotency and has been shown as a useful immunohistochemical marker for germ cell tumors. However, information of SALL4 distribution in normal human tissues and non-germ cell tumors is limited. In this study we examined normal human tissues and 3215 tumors for SALL4 expression using a monoclonal antibody 6E3 and automated immunohistochemistry. In a 10-week embryo, SALL4 was expressed in ovocytes, intestine, kidney, and some hepatocytes. In adult tissues, it was only detected in germ cells. SALL4 was consistently expressed in all germ cell tumors except some trophoblastic tumors and mature components of teratomas, in which it was selectively expressed in intestinal-like and some squamous epithelia. In non-germ cell carcinomas, SALL4 was detected in 20% of cases or more of serous carcinoma of the ovary, urothelial high-grade carcinoma, and gastric adenocarcinoma (especially the intestinal type). SALL4 was only rarely (≤ 5%) expressed in mammary, colorectal, prostatic, and squamous cell carcinomas. Many SALL4-positive carcinomas showed poorly differentiated patterns, and some showed positivity in most tumor cells mimicking the expression in germ cell tumors. SALL4 was commonly expressed in rhabdoid tumors of the kidney and extrarenal sites and in the Wilms tumor. Expression of SALL4 was rare in other mesenchymal and neuroendocrine tumors but was occasionally detected in melanoma, desmoplastic small round cell tumor, epithelioid sarcoma, and rhabdomyosarcoma. All hematopoietic tumors were negative. SALL4 is an excellent marker of nonteratomatous germ cell tumors, but it is also expressed in other tumors, sometimes extensively. Such expression may reflect stem cell-like differentiation and must be considered when using SALL4 as a marker for germ cell tumors. Observed lack of other pluripotency factors, OCT4 and NANOG, in SALL4-positive non-germ cell tumors can also be diagnostically helpful.