Shunichi Sasou

Expression of hepatocyte nuclear factor-1beta (HNF-1beta) in clear cell tumors and endometriosis of the ovary.

Clear cell tumors of the ovary are frequently associated with ovarian endometriosis. Clinicopathologically, it has been suggested that clear cell tumors develop from endometriosis, but there has been little molecular evidence supporting this speculation. Microarray analysis revealed recently that hepatocyte nuclear factor-1beta (HNF-1beta) was significantly upregulated in clear cell carcinoma of the ovary. In the present study, we examined 30 clear cell tumors (26 malignant, three borderline, and one benign) and 40 endometriotic cysts to clarify if differentiation into the clear cell lineage already begins in ovarian endometriosis. All of the 30 clear cell tumors, including borderline and benign ones, showed immunohistochemical expression of HNF-1beta in the nucleus, while other types of ovarian epithelial tumors (endometrioid, serous, mucinous, and Brenner tumors) rarely expressed it. Among 30 clear cell tumors, 17 (56%) cases were associated with endometriosis, and endometriotic epithelium was identified in 12 cases. In nine of the 12 cases, distinct nuclear immunostaining for HNF-1beta was detected in the endometriotic epithelium, as well as in the clear cell tumor. HNF-1beta expression was observed either in atypical endometriosis (four cases), or in endometriosis of a reactive nature (five cases). Furthermore, 16 of 40 (40%) endometriotic cysts without a neoplasm also expressed HNF-1beta, and the expression was almost exclusively observed in the epithelium showing inflammatory atypia. Our results indicate that HNF-1beta is an excellent molecular marker for ovarian clear cell tumors, including benign, borderline and malignant lesions. Early differentiation into the clear cell lineage takes place in ovarian endometriosis, not only in atypical endometriosis, but also in endometriosis with degenerative and regenerative changes, and this is probably responsible for the frequent occurrence of clear cell carcinoma in ovarian endometriosis.

Small cell neuroendocrine carcinomas of the uterine cervix: a histological, immunohistochemical, and molecular genetic study.

Small cell carcinomas of the uterine cervix are rare tumors with an aggressive behavior. Although these tumors can exhibit neuroendocrine differentiation, the criteria for neuroendocrine differentiation are subjective and not well defined. In this study, the authors tentatively defined small cell neuroendocrine carcinoma (SCNEC) as a tumor composed of small cells with at least two of the following: argyrophilic cytoplasm, chromogranin A immunoreactivity, and synaptophysin immunoreactivity. We found 10 cases fulfilling these requirements. Five of the 10 tumors were composed mainly of small (“oat”) cells and 5 of mainly larger “intermediate” cells. The majority of both subtypes showed an insular pattern. Three of the 10 SCNECs were pure, whereas the other seven were mixed with adenocarcinoma and/or squamous cell carcinoma or cervical intraepithelial neoplasia. In addition to the definitional markers noted earlier, the tumors were immunoreactive for serotonin (6 cases), somatostatin (5), gastrin (3), glucagon (1), and pancreatic polypeptide (1). No tumors were immunoreactive for cytokeratin 20. Human papillomavirus (HPV)-18 was detected in all of the pure tumors and both the SCNEC and adenocarcinomatous components in four of the mixed tumors. No other types of HPV were detected. The tumors showed a relatively low frequency of loss of heterozygosity for representative tumor suppressor gene sites; p53 mutations were found in only one case.

A unique method for mutation analysis of tumor suppressor genes in colorectal carcinomas using a crypt isolation technique

BACKGROUND Contamination of nontumor tissue makes genetic analysis difficult. For this reason, it is important to obtain pure tumor tissue to ensure accurate genetic analysis. OBJECTIVE To accurately assess the incidence of mutation of tumor suppressor genes (p53: exon 5-8; APC: mutated cluster region; NF-2 gene: all exons) in 45 colorectal carcinomas. METHODS We developed an application of the polymerase chain reaction-single-strand conformation polymorphism and DNA sequence by coupling them with crypt isolation. RESULTS Mutations of p53 and APC genes were found in 24 and 22 of 45 colorectal carcinomas, respectively. No mutation of the NF-2 gene was observed in this cancer. Single-strand conformation polymorphism using a crypt isolation technique showed a clear migrating band and no false-positive data. CONCLUSIONS The crypt isolation technique is a useful method for accurately analyzing genetic alterations. Furthermore, our proposed method confirmed the morphological findings obtained before the genetic analysis.

KIT expression in normal and neoplastic renal tissues : Immunohistochemical and molecular genetic analysis

Renal chromophobe cell carcinomas (ChCC) and oncocytomas express KIT. This character seems to reflect their common histogenesis from distal nephrons. In the normal kidney, however, the expression and localization of KIT are unclear. KIT expression in angiomyolipoma and congenital mesoblastic nephroma (CMN), is still controversial. c‐kit mutations are reportedly rare in ChCC, but there is little information in other renal neoplasms, and no reported data on mutations of platelet‐derived growth factor receptor (PDGFR). In order to address these issues the authors examined five ChCC, five oncocytomas, seven papillary cell carcinomas, two collecting duct carcinomas, 12 angiomyolipomas, and three CMN, as well as 10 normal renal tissues. In the normal kidney KIT was specifically expressed in the distal nephrons. Nine of 12 (75%) angiomyolipomas contained scattered KIT‐positive cells, whereas all three CMN were completely negative for KIT. The presence of KIT‐positive cells in angiomyolipomas was likely to correspond to that of melanocytic marker‐positive cells, which mainly showed epithelioid morphology. Polymerase chain reaction‐single‐strand conformation polymorphism showed no evidence of mutations of c‐kit or PDGFR in any of the tumors examined.

Primitive neuroectodermal tumor of the breast: Immunohistochemistry and fluorescence in situ hybridization

A case of primitive neuroectodermal tumor (PNET) that developed as a breast lump in a 47‐year‐old Japanese woman is reported. After fine‐needle aspiration (FNA) cytology, a mastectomy was performed. The surgical specimen was a well‐circumscribed tumor, 21 × 18 × 18 mm, localized in the breast. The tumor cells were small and round with scant cytoplasm, and proliferated in sheets or solid nests. No intraductal carcinoma component was present. The tumor cells were immunohistochemically positive for neural cell adhesion molecule (CD56), neuron‐specific enolase and synaptophysin, and they showed membranous immunoreactivity for the MIC2 protein (CD99). Fluorescence in situ hybridization (FISH) indicated a rearrangement of the EWS region on chromosome 22, which is highly specific for Ewings sarcoma and PNET, which are referred to as the Ewings sarcoma family of tumors (EFT). No other lesions suggestive of the primary site of this tumor, such as bone, soft tissue, or other organs were detected. The patient has been disease free for 6 months after surgery followed by chemoradiation therapy. FISH is extremely useful for accurate diagnosis of EFT, especially in cases of unusual locations.

Overexpression of laminin-5 γ2 chain in clear cell carcinoma of the ovary

One of the characteristic microscopic features of ovarian clear cell carcinoma (CCC) is the densely hyaline basement membrane material expanding the stroma. The biological significance of this material, however, has remained unclear. Recent studies have shown that laminin-5 (LN-5), a major component of the epithelial basement membrane, plays a more active role in cell migration or tumor invasion. In the present study, 20 CCCs and 5 borderline clear cell tumors were examined for LN-5 expression immunohistochemically, using an antibody against LN-5 γ2 chain. All of the 20 CCCs showed a focal or diffuse immunoreactivity with the LN-5 γ2 chain in the tumor stroma; whereas, borderline clear cell tumors rarely showed a stromal immunoreactivity. Cytoplasmic accumulation of the LN-5 γ2 chain was far less common than stromal accumulation, suggesting an accelerated secretion in CCC. In vitro, CCC cell lines showed a significant increase in cell migration over excessive LN-5, and the migration was blocked by an antibody against integrin α3. These results indicate that an interaction between CCC cells and extracellularly accumulated LN-5 is responsible for cell migration and the subsequent stromal invasion of CCC.

Multiple carcinoid tumors of the rectum: report of two cases suggesting the origin of carcinoid tumors.

Two cases of multiple carcinoid tumors of the rectum with numerous micronests of carcinoid tumors are reported. The patients were 51‐ and 58‐year‐old males. Many carcinoid tumors and numerous carcinoid micronests were found in the resected rectum; the total number of carcinoid tumors, groups of micronests, and solitary micronests was 69 in the first case and 62 in the second case. The micronests, consisting of a few to many endocrine cells, were observed in the lamina propria, muscularis mucosa, and/or submucosa. Micronests increased in number, gathered and formed carcinoid tumors, which were up to 8 mm in diameter. It was found that a nest of the carcinoid tumors in the lamina propria showed continuity with the endocrine cells of a crypt in the different carcinoid tumors in both cases. The carcinoid tumor and micronest infiltrated the nerves and ganglions in the muscularis mucosa and submucosa. Nests of the carcinoid tumors and micronests were surrounded by S‐100‐positive cells. Lymph node metastases of the carcinoid tumor were found in both cases. Rectal carcinoid tumors may originate from endocrine cells of the crypts, and multiple carcinoid tumors may occur heterogeneously.

Early stage of development in testicular choriocarcinomas

Choriocarcinoma is the most malignant among germ cell tumors in the testis. However little is known about the early stage of its development. To understand the development of testicular choriocarcinomas, twenty cases of testicular choriocarcinoma were studied histologically and immuno‐histochemically. It was found that in the early stage of development, choriocarcinomas imitate the morphologic or functional differentiation of normal trophoblasts. It was also found that some choriocarcinomas regress spontaneously in the early stage. The majority of choriocarcinomas seemed to develop by first going through the embryonal carcinoma phase. However there were some choriocarcinomas that showed no relationship with embryonal carcinoma.

Parathyroid carcinoma with anaplastic feature: Association of a p53 gene mutation with anaplastic transformation

Parathyroid carcinoma is a rare neoplasm that accounts for only 1–3% of cases of primary hyperparathyroidism. Parathyroid carcinoma is a well‐differentiated tumor that is sometimes difficult to differentiate histopathologically from its benign counterpart, parathyroid adenoma. The molecular mechanism of parathyroid carcinogenesis remains unknown, and investigators have reported that abnormalities of the p53 gene do not play a significant role in parathyroid carcinogenesis, unlike in other human malignancies. The present report describes parathyroid carcinoma with anaplastic transformation of differentiated parathyroid carcinoma in a patient with primary hyperparathyroidism. Nuclear accumulation of p53 protein was found in anaplastic carcinoma cells but not in differentiated carcinoma cells. Polymerase chain reaction–single‐strand conformation polymorphism followed by direct sequencing showed that anaplastic carcinoma cells carried a missense mutation at codon 248 (CGG to CAG) of the p53 gene, while the remaining differentiated carcinoma cells had the wild‐type p53 gene. These findings suggest that the p53 gene mutation is associated with anaplastic transformation of parathyroid carcinoma.

SOLITARY MULTILOCULAR CYST OF THE KIDNEY WITH EMBRYONIC TISSUE IN A CHILD

A case of multilocular cyst of the kidney with embryonic tissue has been reported. The patient was a five‐month‐old girl. A large multicystic space occupying lesion was found in the right kidney. Some embryonic renal tissue was observed in the cystic mass by microscopy. The significance of the presence of the embryonic renal tissue in a multilocular cyst of children was discussed referring to other cases reported in the literature.