Pathological complete response following neoadjuvant chemotherapy for locally advanced intrahepatic cholangiocarcinoma

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer. Cases when found are often advanced with vascular invasion, and radical resection is often difficult. Despite curative resection, the postoperative recurrence rate of patients with histological lymph node metastasis is high, and their prognosis is poor. Therefore, there is an urgent need to establish multidisciplinary treatment that combines chemotherapy and surgical resection. The efficacy of neoadjuvant chemotherapy (NAC) for locally advanced ICC is unclear. In this report, a case of locally advanced ICC in which pathological complete response (pCR) was achieved after NAC is described.

CASE PRESENTATION

A 79-year-old woman was admitted to a local hospital with appetite loss. Computed tomography showed a 100 × 90 mm low-contrast tumor in the left hepatic lobe and segment 1 with invasion to the inferior vena cava (IVC), and several lymph nodes along the left gastric artery and lesser curvature were enlarged. Therefore, she was treated with a combined chemotherapy regimen of gemcitabine and cisplatin. After four courses, the tumor size decreased to 30 × 60 mm without invasion to the IVC. Left hepatectomy extending to segment 1 with bile duct resection combined with middle hepatic vein resection (H1234-B-MHV), dissection of regional lymph nodes and pyloroplasty were performed. After radical resection, pCR was achieved. She is alive with no evidence of disease, 2 years after surgery.

CONCLUSIONS

In this case, a patient with locally advanced ICC achieved pCR to NAC. NAC may be effective for ICC. Patients who achieve pCR may have a better prognosis.

Tspan15-ADAM10 signalling enhances cancer stem cell-like properties and induces chemoresistance via Notch1 activation in ICC

BACKGROUND & AIMS

Notch1 activation promotes ICC progression and is associated with chemoresistance; however, therapies directly targeting Notch1 showed severe adverse effects. Notch1 activation is mediated by ADAM10, a molecular scissor that separates the target protein from its substrates in the cell membrane. Tspan15 regulates ADAM10 function, but the role of Tspan15 in ICC progression is unclear.

METHODS

Tspan15, ADAM10, and Notch1 expression and activation in fresh surgical specimens from 80 ICC patients and ICC cells were evaluated by immunohistochemistry, RT-PCR, western blotting, and flow cytometry.

RESULTS

Tspan15 expression was increased in ICC compared with adjacent liver tissue, and high Tspan15 expression was an independent factor for poor prognosis. In ICC with high Tspan15 expression, vascular invasion, lymph node metastasis, and haematogenous recurrence were increased. Tspan15 was co-expressed with ADAM10 in ICC, and associated with the expression of stemness and EMT markers. In ICC cells, Tspan15 induced ADAM10 activation by mediating the translocation of activated m-ADAM10 from the cytoplasm to the surface of the cell membrane, which further activated Notch1 by separating the intracellular domain of Notch1 from its extracellular domain, leading to enhancement of CSC-like properties and EMT. This signalling was associated with enhanced chemoresistance against gemcitabine and cisplatin. Inhibition of Tspan15 or ADAM10 is a promising therapeutic strategy in ICC, as Tspan15 or ADAM10 knockdown or treatment with ADAM10 inhibitor reduced chemoresistance and invasiveness by suppressing Notch1-mediated CSC-like properties and EMT.

CONCLUSIONS

Tspan15-ADAM10-Notch1 signalling is associated with aggressive tumour progression and poor prognosis in ICC.

Determination of Significant Prognostic Factors for Maxillary Gingival Squamous Cell Carcinoma in 90 Cases

Maxillary gingival squamous cell carcinoma (MGSCC) occurs rather infrequently, compared to tongue and mandibular gingival carcinomas, among the cancers of the oral cavity. Therefore, significant numbers of MGSCC cases have not been statistically analysed. The aim of this study is to clarify the prognostic factors for MGSCC. We performed the statistical analysis of 90 MGSCC cases primarily treated in our department from 1999 to 2014. The patients (male: 36, female: 54) were aged between 38 and 93 years, and the mean age was 68.7 years. The number of patients in each tumour stage according to the TNM classification was as follows: T1: 15 cases, T2: 32 cases, T3: 13 cases, and T4: 30 cases. Forty-two patients were treated only by surgery, 5 only by radiotherapy, 3 by preoperative radiotherapy and surgery, and 40 patients were treated by combination therapy with preoperative chemoradiotherapy and surgery. Neck dissections were performed in 40 cases including 29 cases (11 primary and 18 secondary cases) of histopathologically diagnosed lymph node metastases. Extranodal extension was found in 74.3% cases with metastatic lymph nodes. The 5-year overall survival rate was 81.9%. In univariate analysis, the site of occurrence, stage of tumour, lymph node metastasis, and treatment contributed to the 5-year survival rate. Multivariate analysis demonstrated that the site of occurrence (posterior region) was an independent prognostic factor. Seventeen deaths occurred due to the primary disease, while three deaths were caused by other diseases. The posterior region cancers, according to the classification based on site of occurrence, were independent predictors of poor 5-year overall survival rate.

Synchronous early-stage breast cancer and axillary follicular lymphoma diagnosed by core needle biopsy: A case report

Synchronous double cancers are an infrequent finding. The focus of this study was a case of diagnosed synchronous double breast cancer (BC) and axillary (Ax) follicular lymphoma (FL). The patient was a 73-year-old woman who had been visiting her local doctor for follow-up of a fibroadenoma of the left breast, and was referred to our hospital after being diagnosed with invasive ductal carcinoma (IDC) of the left breast. Ultrasonography (US) revealed enlarged Ax lymph nodes (LNs) and US-guided core needle biopsy (CNB) was performed. CNB revealed no metastasis of IDC; however, a diagnosis of FL was made. Therefore, the patient was diagnosed with synchronous double BC and Ax FL and underwent partial surgical resection of the BC and close monitoring of the FL. To the best of our knowledge, this is the first case of malignant lymphoma diagnosed by CNB of Ax LNs during preoperative BC screening. CNB allows for a shorter waiting time for the examination, and it is considered to be minimally invasive, cost-effective and non-inferior to surgical resection in terms of specimen volume. Therefore, active preoperative evaluation of Ax LNs using US-guided CNB may contribute to BC staging, and may also help diagnose synchronous cancers.

Surgical resection of undifferentiated pleomorphic sarcoma (UPS) with jejunal perforation, a suspected case of metastasis of lung cancer

Undifferentiated pleomorphic sarcoma (UPS) in the gastrointestinal tract is rare. According to the diagnostic criteria after the World Health Organization 2013 reclassification, there has been only one case of UPS with perforation of the gastrointestinal tract. A 71-year-old man who was undergoing outpatient chemotherapy at the department of respiratory medicine of our hospital for lung cancer and brain metastasis, was admitted to our hospital with sudden high fever and abdominal pain. A computed tomography scan showed free air in the abdominal cavity with thickening of part of the jejunal wall. We suspected jejunal metastasis of lung cancer and performed emergency surgery for acute peritonitis due to gastrointestinal perforation in the same area. A Bormann type 2 tumour was found in the jejunum with perforation. The histopathological diagnosis was UPS. Ten months have passed since the surgery, and there has been no recurrence of UPS and no significant change in lung cancer. Primary UPS of the gastrointestinal tract is rare, and cases with perforation are extremely rare. Currently, ten months have passed since the surgery, and no recurrence has been observed. We encountered a case of UPS in which it was difficult to distinguish metastasis from lung cancer to the jejunum, and the emergency surgery gave us the chance to confirm the definitive diagnosis and save the patient's life.

CA19-9-producing esophageal adenocarcinoma originating from the esophageal cardia of the mid-thoracic esophagus: a case report

BACKGROUND

Although there are many studies on primary esophageal adenocarcinoma arising from Barrett's esophagus or ectopic gastric mucosa, reports on adenocarcinoma arising from esophageal cardiac glands are extremely rare. Herein, we report a case of mid-thoracic cancer antigen 19-9 (CA 19-9)-producing primary esophageal adenocarcinoma, which presumably originated from the cardiac glands.

CASE PRESENTATION

A 74-year-old man was referred to our department with advanced esophageal cancer, which initially presented with dyspepsia. Serum levels of cancer antigen 19-9 (CA 19-9) were elevated (724.89 U/ml). Upper gastrointestinal endoscopy revealed a type 2 tumor on the posterior wall of the mid-thoracic esophagus approximately 29-32 cm from the incisor. Mucosal biopsy was consistent with a diagnosis of adenocarcinoma. Contrast-enhanced computed tomography showed a circumferential wall thickening in the mid-thoracic esophagus without enlarged lymph nodes or distant metastasis. Positron emission tomography-computed tomography showed accumulation in the primary tumor, but no evidence of lymph node or distant metastasis. According to these findings, the adenocarcinoma was staged as cT3N0M0, thereby, requiring subtotal esophagectomy with lymph node dissection. Postoperative course was uneventful. Histopathologic analysis revealed a 50 × 40 mm moderately differentiated adenocarcinoma with invasion to the thoracic duct and lymph node metastasis at #108(1/4), #109R(1/3), and #109L(1/3). After surgery, the stage was revised to moderately differentiated pT4apN2pM0 (pStage III). Immunostaining revealed expression of CA19-9 and suggested esophageal cardiac gland origin of the tumor. Three months after the surgery, the patient showed no recurrence and is undergoing outpatient observation.

CONCLUSIONS

We experienced a case of mid-thoracic CA19-9-producing primary esophageal adenocarcinoma, which was presumed to have originated in the esophageal cardiac glands. Due to the scarcity of studies regarding this condition, specific management needs to be further clarified.

Clinical impact of the biology of synchronous axillary lymph node metastases in primary breast cancer on preoperative treatment strategy

BACKGROUND AND OBJECTIVES

The purpose of this study was to assess the utility of determining the biological features of synchronous axillary lymph node (syLN) metastasis of breast cancer in evaluating the efficacy of preoperative systemic chemotherapy (PST).

MATERIALS AND METHODS

The retrospective subjects initially comprised 59 patients (T1c-4 N1-3 M0) diagnosed with syLN metastasis via core needle biopsy who received PST. The hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) status in each patient was assessed in primary breast tumor (pBT) and syLNs using immunohistochemistry, and the patients were classified into HR(+), HER2(+), and triple negative breast cancer (TN) subtypes.

RESULTS

Subtype shift (SS) of pBT in syLNs was observed in 28% cases for HR(+), in 6% cases for the HER2(+), and in 16% cases for the TN. The pCR rate of the pBT and syLNs types were 45% and 36% in the HR(+), 45% and 39% in the TN, and 94% and 100% in the HER2(+), respectively. In SS cases, the pCR rate was significantly higher in 75% cases compared with 33% of the no-SS cases.

CONCLUSION

A SS in syLNs was more frequent in HR(+) than in other types.

[A Case of Histological Complete Remission after Chemotherapy for Paraaortic Lymph Node Recurrence after Colon Cancer Surgery]

In September 2013, a 50-year-old woman presented to our hospital with right abdominal pain as the main complaint. Careful examinations led to the diagnosis of ascending colon cancer. In October 2013, resection of the right half colon and removal of the D3 lymph nodes were performed. As postoperative adjunctive chemotherapy, 6 courses of CAPOX therapy were initiated. PET-CT conducted 17 months after the surgery revealed an enlarged right para-aoric lymph nodes and abnormal FDG accumulation. Lymph node recurrence was diagnosed. In April 2015, 10 courses of CAPOX plus BEV therapy, followed by 12courses of capecitabine single agent, were initiated. PET-CT revealed complete remission of the right para-aoric lymph nodes. However, abnormal FDG accumulation was detected in the right ovary and uterine corpus. After careful examinations in March 2017, we performed expanded total hysterectomy, bilateral resection of the appendicular organs, resection of body reticular region, and removal of the lymph nodes and those at the right side of the aorta for the ovarian and uterine cancer. Pathologically, intimal cancer in the right ovary and uterine corpus was diagnosed. Examination of the right para-aoric lymph nodes resected at the same time showed complete remission on images, although histological complete remission was found with scarring. Currently, 63 months after the initial surgery, the patient is alive without recurrence.

[Surgical Treatment for Liver Metastases of Gastric Cancer]

At present, there is no apparent consensus about the indications for hepatectomy for liver metastases of gastric cancer. In this study, we identified factors of poor prognosis to investigate the indications for hepatectomy in 24 cases of hepatectomy for liver metastases of gastric cancer at our hospital during a period from August 2001 to September 2017. The 1-, 3-, and 5- year survival rates in all 24 cases were 63%, 21%, and 17%, respectively. Single variable analysis revealed that significant factors of poor prognosis were 3 or more liver metastases, synchronous liver metastasis, and positive surgical margin. Multivariable analysis revealed that significant independent factors of poor prognosis were synchronous liver metastases(HR 4.71, 95%CI: 1.08-21.79, p=0.040)and positive surgical margin(HR 5.95, 95%CI: 1.56-25.81, p=0.009). These findings indicated that, in cases of metachronous tumors and negative surgical margin, favorable prognosis can be expected following surgical resection for liver metastases of gastric cancer.

Clinical significance of lymphatic and blood vessel invasion in oral tongue squamous cell carcinomas

Although vascular invasion (VI) is recognized as an important predictor of lymph node metastasis and a significant prognostic factor in head and neck squamous cell carcinoma (HNSCC), there is currently no common definition for the pathological evaluation of VI status. We reviewed the medical records of 63 consecutive resected primary oral tongue SCCs (OTSCCs) without preoperative treatment between June 1999 and April 2008, and evaluated VI status by investigating lymphatic vessel invasion (LVI) and blood vessel invasion (BVI) by using immunohistochemistry (IHC) with monoclonal antibody D2-40 (D2-40) and Elastica van Gieson (EVG) staining, respectively. Subsequently, we analyzed their correlations with cervical lymph node metastasis and prognosis. LVI was found in 16 of the 63 tumors (25.4%) and BVI was in 32 tumors (50.8%). Univariate analysis revealed that the presence of LVI is statistically correlated with lymph node metastasis. Moreover, multivariate logistic regression analysis revealed that LVI is an independent risk factor of nodal metastasis (odds ratio=4.262, 95% confidence interval=1.262-14.397, p=0.020). In contrast, Kaplan-Meier survival analysis revealed that patients with BVI had a significantly shorter disease-free survival (DFS) and overall survival (OS) rates than those without BVI (68.6% versus 90.3%, p=0.028 and 68.6% versus 93.5%, p=0.013, respectively). The present study clearly demonstrated that LVI at primary OTSCC had significant correlation with lymph node metastasis, and that BVI was significantly associated with recurrence and poor prognosis. Evaluation of VI status, as LVI and BVI status separately, using IHC with D2-40 and EVG staining may be useful in predicting lymph node metastasis and poor prognosis in OTSCCs.

EGFR gene copy number alteration is a better prognostic indicator than protein overexpression in oral tongue squamous cell carcinomas

Although epidermal growth factor receptor (EGFR) is particularly important in the pathogenesis of head and neck squamous cell carcinomas (HNSCCs), conflicting data have been reported on the correlation between EGFR copy number and survival and the association between EGFR copy number and protein expression. Anatomical site of the tumour in HNSCCs may likely contribute to the discordance of the above points as EGFR expression may differ between the sub-sites of HNSCCs. Thus, in this study, we focused on oral tongue squamous cell carcinomas (OTSCCs). To investigate the association between EGFR copy number alteration and overexpression and to determine which is the more reliable prognostic indicator, Fluorescence in situ hybridisation (FISH) and immunohistochemical staining (IHC) were performed at a single institution on samples from 89 patients with OTSCCs undergoing surgery as the primary treatment modality. Thirty-two (36%) of 89 cases demonstrated an EGFR copy number alteration. EGFR protein expression was found in all 89 cases, of which 82.0% showed overexpression. No significant correlation was found between gene copy number and protein overexpression. Gene copy number alteration was significantly associated with reduced disease-free survival (P=0.048) and overall survival (P=0.001). Multivariate Cox proportional hazards analysis demonstrated that EGFR copy number increase was significantly correlated with overall survival (P=0.001). EGFR copy number status is a more reliable indicator than protein overexpression of the survival rate in OTSCCs. FISH analysis of the EGFR status is useful in predicting poor prognosis in OTSCCs.

Fluorescence in situ hybridization for detecting genomic alterations of cyclin D1 and p16 in oral squamous cell carcinomas

BACKGROUND

Cyclin D1 (CCND1) and p16 alterations have been detected in oral squamous cell carcinomas (SCCs), suggesting that abnormalities of these genes may play an important role in the genesis or progression of oral SCCs and serve as independent prognostic indicators. The detection of CCND1 and p16 aberrations using a simple and sensitive method would be valuable for the development of effective treatment modalities for oral cancer. The objective of the current study was to determine whether CCND1 numerical aberrations and p16 deletions in oral SCCs detected by fluorescence in situ hybridization (FISH) have any impact on clinical outcome.

METHODS

Using genomic DNA probes for CCND1 and p16, FISH was performed on specimens that were obtained by fine-needle aspiration (FNA) from 57 primary oral SCCs.

RESULTS

The CCND1 numerical aberration was observed in 28 of 57 patients (49%) with oral SCCs and was associated significantly with reduced disease-free survival (P = .0004) and overall survival (P = .0179). Conversely, p16 deletion was detected in 22 of 57 patients (39%). The disease-free and overall survival rates for patients with p16 deletion were lower than those among patients without the p16 deletion, although the difference just failed to reach statistical significance (P = .0516 and P = .1878, respectively). The p16 deletion in the presence of the CCND1 numerical aberration conferred significantly worse disease-free survival (P = .0002) and overall survival (P = .0153).

CONCLUSIONS

Although the CCND1 numerical aberration was a good predictor of aggressive tumors, recurrence, and poor prognosis in patients with oral SCCs, the authors were able to identify subgroups of patients that had early disease recurrence and a poor prognosis more efficiently by assessment of p16 deletion in addition to CCND1 genetic status using FISH on FNA biopsy samples compared with the analysis of either alteration alone.

Cyclin D1 gene numerical aberration is a predictive marker for occult cervical lymph node metastasis in TNM Stage I and II squamous cell carcinoma of the oral cavity

BACKGROUND

The management of occult cervical lymph node metastases originating from oral squamous cell carcinomas (OSCCs) remains controversial. The purpose of this study was to evaluate the value of cyclin D1 gene (CCND1) numerical aberrations in predicting the risk of late lymph node metastases.

METHODS

Fluorescence in situ hybridization (FISH), using a BAC clone specific for CCND1, was performed on OSCC specimens obtained by fine-needle aspiration (FNA) biopsy from 45 patients with previously untreated TNM Stage I and II (T1-2N0M0) disease who had not undergone elective cervical lymph node dissection.

RESULTS

CCND1 numerical aberrations were observed in 15 (33.3%) of the 45 patients and were significantly associated with the mode of invasion of the primary tumor (P = 0.01) and the presence of occult lymph node metastases (P < 0.001). Twelve of these 15 patients (80%) developed late cervical lymph node metastases within 2 years of surgery for primary OSCCs. All patients with cluster-type amplification of CCND1 developed late lymph node metastases. Multivariate analysis showed that only CCND1 numerical aberrations (risk ratio, 8.685%, 95% confidence interval = 2.232-33.802, P = 0.002) independently predicted late cervical lymph node metastasis.

CONCLUSIONS

Aberrations in CCND1 numbers appear to be valuable in identifying patients at high risk of late lymph node metastasis in Stage I and II OSCCs. Analysis of CCND1 numerical aberrations using FISH on FNA biopsy specimens may be useful in selecting patients for elective cervical lymph node dissection.

Screening of DNA copy-number aberrations in gastric cancer cell lines by array-based comparative genomic hybridization

We performed genome-wide screening for deoxyribonucleic acid copy-number aberrations in 31 gastric cancer (GC) cell lines by using custom-made comparative genomic hybridization (CGH)-array. Copy-number gains were frequently detected at 1q, 3q, 5p, 7p, 7q, 8q, 11q, 17q, 20p, 20q, Xp and Xq, and losses at 3p, 4p, 4q, 8p, 9p, 18p and 18q. With respect to histological subtypes, copy-number gains at 1p, 16p, 20p, 20q and 22q, and losses at 8p, 10p, 10q and 18q were significantly frequent in cell lines derived from tumors of the well-differentiated type, whereas copy-number gains at 1q, 7p, 7q, Xp and Xq were frequent in the undifferentiated type. Homozygous deletions were seen at five loci, whereas high-level amplifications were detected in 15 of the 31 GC cell lines; these had occurred at 24 loci, including the segment containing CDK6 (7q21.2). Amplification of that gene had never been reported in GC before. Immunohistochemical studies showed increased levels of CDK6 protein in 54 of the 292 primary GC samples we examined (18.5%). Cytoplasmic localization of CDK6, as well as CDK6 over-expression, was more frequent in well-differentiated GC than in undifferentiated tumors. Nuclear expression of CDK6 was more frequent in early stage GC than in advanced tumors, suggesting that nuclear localization of CDK6 is likely to be a prognostic factor for GC. Taken together, our data indicate that CDK6 might be involved in the pathogenesis of GC and, more generally, that CGH-arrays have a powerful potential for identifying novel cancer-related genetic changes in a variety of tumors.

Involvement of overexpressed wild-type BRAF in the growth of malignant melanoma cell lines

Comparative genomic hybridization (CGH) using 40 cell lines derived from malignant melanomas (MMs) revealed frequent amplification at 7q33-q34 containing BRAF gene, which often is mutated in MM. We found this gene to be amplified to a remarkable degree in the MM cell lines that exhibited high-level gains at 7q33-q34 in CGH. Among 40 cell lines, the eight lines that revealed neither BRAF nor NRAS mutations showed even higher levels of BRAF mRNA expression than the 32 mutated lines, although DNA amplification at 7q33-q34 was not detected in every lines overexpressing BRAF. MM cells that carried wild-type BRAF and NRAS showed constitutive overexpression of B-Raf protein and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), even after serum starvation. Not only downregulation of the endogenously overexpressed wild-type B-Raf by antisense oligonucleotide but also a treatment with an inhibitor of mitogen-activated protein kinase kinase (MAPKK, MEK) reduced phosphorylated ERK1/2 and cell growth, whereas the exogenously expressed wild-type B-Raf promoted cell growth in MM cells. Our results provide the evidence that overexpression of wild-type B-Raf, in part but not always as a result of gene amplification, is one of the mechanisms underlying constitutive activation of the MAPK pathway that stimulates growth of MM cells.

Frequent silencing of low density lipoprotein receptor-related protein 1B (LRP1B) expression by genetic and epigenetic mechanisms in esophageal squamous cell carcinoma

Low-density lipoprotein receptor-related protein 1B (LRP1B) is frequently deleted in tumors of various types, but its status and expression in esophageal squamous cell carcinomas (ESCs) have never been reported. In the course of a program to screen ESC cell lines for copy-number aberrations using array-based comparative genomic hybridization, we identified a homozygous deletion of LRP1B. Genomic PCR experiments revealed homozygous deletions of LRP1B in additional ESC cell lines (total, 6 of 43; 14.0%) and in primary esophageal tumors (30 of 70; 42.9%). Moreover, expression of LRP1B mRNA was frequently silenced in ESC lines without homozygous deletions (14 of 37; 37.8%). Using bisulfite-PCR analysis and sequencing, we found that LRP1B-nonexpressing cells without homozygous deletions were highly methylated at a CpG island of LRP1B, a sequence possessing promoter activity. Treatment with 5-aza-2'-deoxycytidine restored expression of LRP1B in those ESC lines. Histone acetylation status correlated directly with expression of LRP1B and inversely with the methylation status of the CpG island. Methylation of LRP1B was also detected in primary esophageal tumors. Restoration of LRP1B expression in ESC cells reduced colony formation. These results suggest that loss of LRP1B function in esophageal carcinogenesis most often occurs either by homozygous deletion or by transcriptional silencing through hypermethylation of its CpG island.

Identification of ZASC1 encoding a Krüppel-like zinc finger protein as a novel target for 3q26 amplification in esophageal squamous cell carcinomas

Among the transcription factors that direct proliferation, differentiation, and death of cells, several Krüppel-like zinc finger molecules such as GLI1 and ZNF147 can become oncogenic when the genes encoding them are overexpressed by the DNA amplification mechanism. Here, we report the discovery of a novel member of this class, ZASC1, from a recently reported critical region of 3q26 amplification frequently observed in various squamous cell carcinomas, including esophageal squamous cell carcinomas (ESCs). The deduced 485-amino acid protein product of ZASC1 contained a putative nuclear localization signal; the exogenously transfected ZASC1 was translocated into cell nuclei. ZASC1 was frequently coamplified and subsequently overexpressed with PIK3CA in our panel of ESC cell lines and primary tumors. In patients with ESC, a higher mRNA expression level of ZASC1 appeared to be associated with shorter overall survival, and a multivariate analysis demonstrated that ZASC1 mRNA expression was an independent prognosticator. In addition, exogenous expression of ZASC1 promoted the growth of ESC cells, whereas down-regulation of ZASC1 expression by means of an antisense oligonucleotide suppressed the growth of ESC cells. Taken together, our results suggest that ZASC1 might be involved in the pathogenesis of ESC as one of the targets for 3q26 amplification, alone or in concert with other targets.

Identification and characterization of human PKNOX2, a novel homeobox-containing gene

The three-amino-acid loop extension (TALE) homeodomain proteins are highly conserved transcription regulators. Since cooperative function among members of this growing family is critical for regulating transcription, we have tried to explore novel members to understand their regulatory mechanisms in cellular proliferation and differentiation. Here we report identification of PKNOX2, a novel TALE homeodomain protein that shows distinct homology with PKNOX1, a stable partner of PBX proteins. PKNOX2 is composed of 460 amino acids and contains HR1, HR2, and homeodomain, which are highly similar to PKNOX1, suggesting that PKNOX2 may also interact with PBX proteins as well as the same DNA sequence as PKNOX1. Genomic organization of PKNOX2 also showed high similarity to PKNOX1, though PKNOX2 lies on a different chromosomal region, 11q24. Unlike PKNOX1, which was broadly expressed in many tissues, PKNOX2 showed a more restricted pattern of mRNA expression. Nuclear localization of PKNOX2 was confirmed by transfection of epitope-tagged cDNA. Taken together, these data indicate that PKNOX2 is a novel PKNOX-related protein and may interact with PBX proteins and play a tissue-specific regulation of transcription.

Malignant paraganglioma metachronously recurring at short duration in different paraganglions: report of a case

We report the rare case of a 57-year-old man with retroperitoneal malignant paraganglioma. He was referred to our hospital complaining of left lower abdominal dull pain. Computer tomography (CT), magnetic resonance imaging, and aortography showed a mass measuring 5 x 4 cm in size on the left side of the abdominal aorta below the renal artery. The resected tumor was confirmed histologically to be malignant paraganglioma. Irradiation of the resected area was performed. Four months after the operation, an abdominal CT scan showed a 5.5 x 3.0 cm mass on the right side of the aorta below the diaphragm. This tumor was thereafter also resected. Three months after the second operation, a soft subcutaneous nodule measuring 4.5 x 2.0 cm in size was palpable above the left clavicle and was visible on a CT scan. A resection was again performed. All tumors showed the same histological findings. This is the first case reported in the Japanese literature with such a short-term demonstration of multiple metachronous recurrences in different paraganglions.