Inhibition of β-Catenin Activity Abolishes LKB1 Loss-Driven Pancreatic Cystadenoma in Mice

Pancreatic cancer (PC) is the seventh leading cause of cancer death worldwide, and remains one of our most recalcitrant and dismal diseases. In contrast to many other malignancies, there has not been a significant improvement in patient survival over the past decade. Despite advances in our understanding of the genetic alterations associated with this disease, an incomplete understanding of the underlying biology and lack of suitable animal models have hampered efforts to develop more effective therapies. LKB1 is a tumor suppressor that functions as a primary upstream kinase of adenine monophosphate-activated protein kinase (AMPK), which is an important mediator in the regulation of cell growth and epithelial polarity pathways. LKB1 is mutated in a significant number of Peutz–Jeghers syndrome (PJS) patients and in a small proportion of sporadic cancers, including PC; however, little is known about how LKB1 loss contributes to PC development. Here, we report that a reduction in Wnt/β-catenin activity is associated with LKB1 tumor-suppressive properties in PC. Remarkably, in vivo functional analyses of β-catenin in the Pdx-1-Cre LKB1^L/L β-catenin^L/L mouse model compared to LKB1 loss-driven cystadenoma demonstrate that the loss of β-catenin impairs cystadenoma development in the pancreas of Pdx-1Cre LKB1^L/L mice and dramatically restores the normal development and functions of the pancreas. This study further determined the in vivo and in vitro therapeutic efficacy of the β-catenin inhibitor FH535 in suppressing LKB1 loss-driven cystadenoma and reducing PC progression that delineates the potential roles of Wnt/β-catenin signaling in PC harboring LKB1 deficiency.

[Borderline ovarian tumors and global radiation in relation with climate change impact]

There is limited information on borderline ovarian tumor detected intra-surgically and its most favorable treatment in relation with global radiation and climate changes.

AIM

To study the pre-surgery and intra-surgery differentiation criteria of borderline ovarian tumors from invasive carcinoma, and to make a very complex analysis of the frequency, distribution, and variation in time of global radiation, temperature, and precipitation in North-East Romania.

MATERIAL AND METHOD

The 54 patients (age range 20-78 years, mean age 46 years) included in this study had borderline ovarian tumors surgically treated during the last 22 years (January 1988 - December 2009) at the 4th Gynecological Clinic at Iaşi, and representing 4.87% of the total 1107 ovarian tumors detected and treated during this interval. The histological types were: serous (18 cases), mucinous (27 cases), mixed (8 cases), and Brenner tumor (1 case). In order to analyze the impact of climate changes on borderline ovarian tumors a thorough study on the frequency of global radiation in relation with climate changes based on data recorded in the last 55 years was also carried out.

RESULTS

The distribution of these cases depending on when surgery was performed was analyzed. In our study the frequency of ovarian borderline tumors (4.87%) is lower than in similar reports in the literature being due, in our opinion, to the influence of global radiation in relation with climate changes.

CONCLUSIONS

In our study global radiation is probably responsible for a progression to invasive carcinoma in 0.7% of the borderline ovarian tumors.

Paratesticular mucinous cystadenoma arising from an oviduct-like müllerian remnant: a case report and review of the literature

A mucinous cystadenoma of the paratestis arising from an unequivocal oviduct-like structure in an 18-year-old man is reported. Mucinous cystadenomas of the testis and paratestis are extremely rare benign tumors of controversial origin. The diagnosis may be challenging and is of clinical importance because these lesions may mimic a teratoma, and teratomas in postpubertal males carry a malignant potential regardless of the degree of maturation. A few case reports and reviews of testicular and paratesticular mucinous neoplasms resembling ovarian tumors have suggested the possibility of a müllerian origin of these tumors. However, no histologic evidence has been found to support such a histogenesis. The current case demonstrates a clear transition from müllerian-type tubal epithelium to intestinal-type mucinous epithelium. This finding, in conjunction with immunophenotypic studies, strongly supports a derivation from a paratesticular müllerian remnant. To our knowledge this represents the first substantial evidence that, in at least some cases, mucinous cystadenomas of the testis and paratestis are of müllerian derivation.

Recurrent endocervical-like mucinous borderline tumor (ELMBT) arising in a case of long-standing endometriosis--a case report

Endometriosis is a well-known precursor lesion of ovarian malignancies, particularly those of endometrioid and clear-cell types and rarely of serous or mucinous types. The association of endometriosis with mucinous borderline tumors also varies. This case is of a 60 year old female, who had a long history of more than thirty years of endometriosis and developed recurrent endocervical-like mucinous borderline tumor (ELMBT) in endometriotic foci. This case highlights challenges in the management of such complications associated with endometriosis and emphasizes the importance of long-term follow-up in cases of endometriosis.

Appendiceal tumour--retrospective clinicopathological analysis

Appendiceal tumours are rare and often discovered unexpectedly in an acute situation in which decision-making is difficult. We report the spectrum of appendiuar tumours seen in our institution over a period of more than 10 years, and discuss the clinicopathological behaviour, investigations, surgical procedures and outcomes in these patients. We have also reviewed the literature with regard to appendiceal tumours. Appendicular tumours were identified from the database of 1646 appendictomies (18% in children) performed in single centre and case notes were reviewed. Clinical presentation, investigations, histopathology, surgical procedures and outcome were analysed. Twelve patients with appendiceal tumours were identified (0.72%): 8 carcinoid, 2 mucinous (mucocele) and 2 adenocarcinoma. All the patients with a carcinoid tumour presented with features suggestive of acute appendicitis and were diagnosed postoperatively following appendicectomy and formal histology. No further surgical intervention was required as these lesions were less than 1cm away from the base of the appendix. One of the patient with mucinous cystadenoma presented acutely and underwent an appendicectomy; in the other patient with chronic pain, apreoperative MRI suggested the diagnosis leading to a planned hemicolectomy as the lesion was close to the base of the appendix. While one of the patient with an adenocarcinoma localized to the appendix did well following a right hemicolectomy, the other patient with disseminated disease succumbed within a year. Carcinoid tumours are the commonest appendiceal tumours, which present often as acute appendicitis. While appendicectomy would be adequate in most of these patients, in patients with a cystadenoma close to the base of the appendix or in case of a carcinoma, a right hemicolectomy is the appropriate option. While the prognosis is good in patients with carcinoid tumour and cystadenoma, it remains dismal in patients with disseminated malignant disease.

Retroperitoneal mucinous cystadenoma

Primary retroperitoneal mucinous cystadenoma is an uncommon tumor found exclusively in women. Herein, we describe a patient who had resection of a large retroperitoneal cystic mass. Histologic, immunohistochemical, and electron microscopic examination of the lining epithelial cells showed features of mesothelial cells in addition to ovarian mucinous cystadenoma. These findings suggest that these tumors arise from inclusions of mesothelial cells and subsequent mucinous metaplasia of the lining cells to form a cystadenoma. Estrogen receptors may be implicated in tumor promotion, explaining the occurrence exclusively in women.

Histochemical analysis of estrogen and progesterone receptors and gastric-type mucin in mucinous ovarian tumors with reference to their pathogenesis

BACKGROUND

Mucinous tumors of the ovary have been thought to originate in two ways: by müllerian-type metaplasia of surface epithelium, and as monodermal teratomas. To gain a better understanding of their pathogenesis, the authors analyzed these tumors for their expression of estrogen receptors (ER) and progesterone receptors (PR) as markers of müllerian-type differentiation and for their content of gastric-type mucin as a marker of gastric differentiation.

METHODS

The histochemical expression of ER, PR, and gastric-type mucin was studied in 10 specimens of the cervix with normal endocervical glands (as a representative of müllerian-derived mucin-containing cells), 3 ovary specimens with surface epithelial inclusion cysts that contained endocervical-like mucin-containing cells (representing müllerian-type metaplasia), and 47 mucinous tumors of the ovary (29 benign, 8 with low malignant potential, and 10 malignant).

RESULTS

Normal endocervical glands expressed ER and PR and rarely expressed gastric-type mucin. Ovarian inclusion cysts showed strong expression of ER and PR in the cuboidal cells and drastically reduced expression in the endocervical-like mucin-containing cells. The cuboidal cells were negative for gastric-type mucin, but the endocervical-like mucin-containing cells expressed gastric-type mucin. Endocervical-like mucinous cells in benign and borderline mucinous tumors showed expression of PR and/or gastric-type mucin in all cases.

CONCLUSIONS

The staining results for the inclusion cysts support the thesis that the endocervical-like mucinous cells encountered in the ones that express ER and PR weakly or not at all and have histochemical properties of normal gastric epithelium have their origin in metaplasia of müllerian-type epithelium. Application of the same staining methods to benign ovarian tumors and those with low malignant potential suggests strongly that similar müllerian-type metaplasia is a major pathway in their pathogenesis.

Two cases of ovarian tumours in women who had undergone multiple ovarian stimulation attempts

Concerns have been raised recently about the possible association between superovulation and ovarian cancer. In order to contribute to the limited literature on this important issue, two cases of ovarian tumours in women who had undergone multiple ovulation inductions are presented. In the first case, the patient had secondary anovulatory infertility. She was treated with human menopausal gonadotrophin (HMG) alone and in combination with clomiphene citrate or buserelin for six cycles. She then underwent ovarian stimulation with buserelin/HMG in the long protocol for in-vitro fertilization (IVF) and embryo transfer. In preparation for a new IVF/embryo transfer attempt, 8 months later, the screening ultrasound revealed a cystic formation of the left ovary and an enlargement of the right. During laparotomy, both ovaries were found to bear large tumours (approximately 6 x 5 x 4 cm) which were removed. Histological examination showed that they were epithelial tumours (serous-papillary cystadenomas) of borderline malignancy. The patient conceived spontaneously 1.5 years after the operation. In the second case, the patient presented with secondary anovulatory infertility. She underwent ovulation induction with clomiphene/HMG and with buserelin/HMG in the long protocol, and intra-uterine insemination with husband's spermatozoa and conceived (singleton pregnancy). She was delivered by Caesarean section, during which a cystic tumour of the left ovary was removed. Histological examination revealed a benign mucous cystadenoma of the ovary.(ABSTRACT TRUNCATED AT 250 WORDS)