Phenotypic alteration in malignant transformation of colonic villous tumours: with special reference to a comparison with tubular tumours

CD10 and CD34 as markers in vascular malformations with PIK3CA and TEK mutations

AIMS

Vascular malformations (vMs) encompass a wide range of diseases often associated with somatic or, more rarely, germinal genetic mutations. A mutation in the PIK3Ca/mTOR pathway is more often involved in various vMs. CD10 and CD34 are cellular markers that may play a role in mesenchymal differentiation and proliferation. The aim of our study was to find a possible link between the immunohistochemical expression of CD10 and CD34 in vMs and their relationship with mutations in the PIK3CA/mTOR signaling pathway.

METHODS AND RESULTS

Our study on 58 samples of vMs showed that in endothelial cells, CD10 was significantly expressed in PIK3CA-mutated samples compared with samples without any mutation (p < 0.05), especially and even more consistently when compared with samples with mutation in other pathways (p < 0.0001). Conversely, in the same PIK3CA-mutated samples, CD34 expression in endothelial cells was significantly reduced compared with samples either without any mutation or mutations in other pathways (p < 0.05 and p < 0.0005). Compared with samples with mutations in other pathways, a significant overexpression of endothelial CD10 was also found in samples with TEK/TIE2 mutation, a gene linked to the PIK3CA/mTOR pathway (p < 0.01). However, CD34 expression was not altered. In samples with PIK3CA mutation, the CD10 expression was significantly increased in the stroma compared with samples with TEK/TIE2 gene or other gene mutations (p < 0.05).

CONCLUSION

Therefore, the CD10 and CD34 immunohistochemical profile could suggest/support the presence of mutations in the PIK3CA/mTOR pathway in samples of vMs.

Clinicopathological features and phenotypic classification of de novo-type colorectal carcinomas differ from those of colorectal carcinomas derived from flat adenomas

Since adenoma components disappear with tumor progression, it is not known whether colorectal carcinomas (CRCs) are derived from an adenoma-carcinoma sequence or are de novo. We compared 38 cases of ≤10-mm flat CRCs without an adenoma component (de novo type) with 39 cases of ≤10-mm flat CRCs with an adenoma component (carcinoma in adenoma (CIA) type). Compared to the CIA type, the de novo-type CRCs were more frequently located in the proximal colon; more frequently invaded submucosa, and more frequently had venous permeation. Regarding the phenotypic classification based on the immunohistochemical expressions of CD10, MUC2 and MUC5AC, the incidence of unclassified type (CD10-, MUC2- and MUC5AC-) was significantly more frequent in the de novo (32%) than CIA (5%) type. In one de novo-type case, mismatch repair (MMR) protein loss was judged, because MLH1 and PMS2 protein expressions were immunohistochemically negative. BRAF mutation (V600E) was seen in one de novo-type case and two CIA-type cases, but none of these cases had MMR protein loss. In conclusion, small-intestinal type (CD10+ and MUC5AC-) is the most common in flat CRC and unclassified type is mainly characteristic of de novo type. In this study, small flat CRCs with BRAF mutation do not have MMR protein loss.

Ectopic Gastric and Intestinal Phenotypes, Neuroendocrine Cell Differentiation, and SOX2 Expression Correlated With Early Tumor Progression in Colorectal Laterally Spreading Tumors

INTRODUCTION

The significance of the ectopic gastric phenotype remains unclear in patients with colorectal laterally spreading tumors (LSTs). We investigated clinicopathologic differences among LST subtypes, aiming to identify factors indicative of malignant transformation and invasion that are linked to ectopic gastric phenotype and tumor progression.

MATERIALS AND METHODS

We analyzed the morphologic characteristics of 105 colorectal LSTs resected by endoscopic submucosal dissection. LSTs were classified into 2 subtypes: granular (G-LST) and nongranular (NG-LST). Resected LSTs were analyzed histologically and were immunohistochemically stained for MUC5AC, MUC6, chromogranin A, CD10, and SOX2.

RESULTS

The 105 LSTs included 60 G-LSTs and 45 NG-LSTs. By histology, G-LSTs comprised 5 adenomas with low-grade dysplasia (LAs), 45 adenomas with high-grade dysplasia (HAs), and 10 adenocarcinomas invading the submucosa (SMs). NG-LSTs comprised 8 LAs, 25 HAs, and 12 SMs. MUC5AC positivity was significantly higher in G-LSTs compared to NG-LSTs (P = .002), and MUC5AC positivity in HA lesions was significantly higher than in LA lesions (P = .01). MUC6 and SOX2 positivity in SM G-LSTs, and chromogranin A positivity in SM NG-LSTs were significantly higher than in HAs (P = .01, .01, and .03, respectively). CD10 positivity in SM NG-LSTs was significantly higher than in HAs and LAs (P = .02 and .01, respectively).

CONCLUSION

Ectopic gastric and intestinal phenotypes, neuroendocrine cell differentiation, and SOX2 expression differ according to tumor grade in colorectal LSTs, and these markers are correlated with early tumor progression in each LST subtype.

Adenoma-like adenocarcinoma: a subtype of colorectal carcinoma with good prognosis, deceptive appearance on biopsy and frequent KRAS mutation

AIMS

A subset of colorectal carcinomas (CRCs) architecturally and cytologically resembles adenomatous change, making them difficult to diagnose on biopsy. This subset has not been well characterized to date.

METHODS AND RESULTS

For 35 carcinomas with adenomatous-like areas (cytological and surface architectural appearance that would be insufficient to warrant a diagnosis of adenocarcinoma if evaluated on biopsy), we recorded staging information, molecular data, clinical outcome, whether precursor adenoma was present and whether previous biopsy had been diagnosed as malignant. Despite advanced T-category in 23 (66%) tumours, only seven (20%) had nodal metastases, and only five patients (15%) developed distant metastases. Fifteen cases (43%) had been diagnosed as adenoma on biopsy. Twenty-one resections (60%) showed no residual associated adenoma, including nine called adenoma on biopsy. Median follow-up was 44 months. Four patients (12%) died of disease; 22 were alive at last follow-up. KRAS mutation was seen in 14 of 24 (58%) and four of 17 (24%) were microsatellite-unstable. Patients had significantly improved survival compared to a cohort of patients with conventional well-differentiated CRC after controlling for age and stage (P = 0.011).

CONCLUSIONS

Adenoma-like adenocarcinoma is an uncommon variant of CRC with a low rate of metastasis and good prognosis. Biopsy diagnosis of this lesion may be challenging.

MUC5AC/β-catenin expression and KRAS gene alteration in laterally spreading colorectal tumors

AIM: To clarify differences in mucin phenotype, proliferative activity and oncogenetic alteration among subtypes of colorectal laterally spreading tumor (LST).

METHODS: LSTs, defined as superficial elevated lesions greater than 10 mm in diameter with a low vertical axis, were macroscopically classified into two subtypes: (1) a granular type (Gr-LST) composed of superficially spreading aggregates of nodules forming a flat-based lesion with a granulonodular and uneven surface; and (2) a non-granular type (NGr-LST) with a flat smooth surface and an absence of granulonodular formation. A total of 69 LSTs, comprising 36 Gr-LSTs and 33 NGr-LSTs, were immunohistochemically stained with MUC2, MUC5AC, MUC6, CD10 (markers of gastrointestinal cell lineage), p53, β-catenin and Ki-67 antibodies, and examined for alteration in exon 1 of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and exon 15 of v-raf murine sarcoma viral oncogene homologue B1 (BRAF) by polymerase chain reaction followed by direct sequencing.

RESULTS: Histologically, 15 Gr-LST samples were adenomas with low-grade dysplasia (LGD), 12 were high-grade dysplasia (HGD) and 9 were adenocarcinomas invading the submucosa (INV), while 12 NGr-LSTs demonstrated LGD, 14 HGD and 7 INV. In the proximal colon, MUC5AC expression was significantly higher in the Gr-type than the NGr-type. MUC6 was expressed only in NGr-LST. MUC2 or CD10 did not differ. P53 expression demonstrated a significant stepwise increment in progression through LGD-HGD-INV with both types of LST. Nuclear β-catenin expression was significantly higher in the NGr-type. Ki-67 expression was significantly higher in the Gr-type in the lower one third zone of the tumor. In proximal, but not distal colon tumors, the incidence of KRAS provided mutation was significantly higher in the Gr-type harboring a specific mutational pattern (G12V). BRAF mutations (V600E) were detected only in two Gr-LSTs.

CONCLUSION: The two subtypes of LST, especially in the proximal colon, have differing phenotypes of gastrointestinal cell lineage, proliferation and activation of Wnt/β-catenin or RAS/RAF/extracellular signal-regulated kinase signaling.

Mucin phenotype and narrow-band imaging with magnifying endoscopy for differentiated-type mucosal gastric cancer

BACKGROUND

Several studies have described the surface glandular structure in differentiated early gastric cancer observed by narrow-band imaging with magnifying endoscopy (NBI-ME) in two main patterns, i.e., a papillary or granular structure in an intralobular loop pattern (ILL) and a pit structure in a fine network pattern (FNP). However, it is uncertain why the NBI-ME findings of differentiated-type carcinomas are divided into two main patterns. We investigated the significance of the mucin phenotype in the morphogenetic difference between ILL and FNP.

METHODS

We evaluated 120 intramucosal, well- or predominantly well-differentiated tubular adenocarcinomas. In each lesion, one area that showed the predominant pattern of microsurface structures and microvessels was selected and marked by electrocoagulation for a strict comparative study by NBI-ME and pathological investigation. NBI-ME findings were classified into three patterns: ILL, FNP, and intermediate. Mucin phenotypes were judged as gastric, intestinal, or gastrointestinal type by immunohistochemistry.

RESULTS

The mucin phenotype was gastric or gastrointestinal type in 24 (92.3%) of 26 ILL lesions. Intestinal phenotype was observed in 22 (84.6%) of 26 FNP lesions. The gastrointestinal phenotype was observed in 50 (73.5%) of 68 intermediate pattern lesions. The mucin phenotype and NBI-ME results were significantly correlated (P < 0.001).

CONCLUSIONS

The mucin phenotype of differentiated early gastric cancer might be involved in morphogenetic differences between the papillary and pit structures visualized by NBI-ME.

Filiform serrated adenomatous polyposis arising in a diverted rectum of an inflammatory bowel disease patient

A 54-year-old man, previously colectomized for inflammatory bowel disease, developed carcinoma in the inflamed rectum stump. The malignant growth was surrounded by a filiform polyposis, grossly considered as pseudopolyps. The histology disclosed, however, a morphology corresponding to the recently described filiform subset of serrated adenoma (FSA). The clustering of the FSA amounted to a filiform serrated adenomatous polyposis, a hitherto unreported observation. It is speculated that neoplastic transformation of pre-existing pseudopolyps and prolaps-related events lead to this peculiar morphology. Minor zones with a villous structure were admixed as were small areas of traditional serrated adenoma and patches of flat dysplasia. Although a combined gastric and intestinal (positivity for MUC5AC, MUC2, MUC6, CDX2) immunoprofile characterized the adenomatous component, a downregulation of the gastric mucin along with a loss of the serrated attribute accompanied the malignant transformation. An added dynamic shift during the adenoma carcinoma sequence included the acquisition of CK7 expression in the malignant portion. Gastric mucin may play a role in the initial step of the neoplastic evolution and CK7 may denote neoplastic progression. This case confirms the notion of a widely variegated morphology of precursor lesions of colorectal carcinoma arising in a chronically inflamed bowel as opposed to the generally more monotonous appearance of adenomas in a sporadic context.

Flat adenoma-carcinoma sequence with high-malignancy potential as demonstrated by CD10 and beta-catenin expression: a different pathway from the polypoid adenoma-carcinoma sequence

AIMS

CD10+ colorectal carcinomas have a high risk of giving rise to liver metastasis. The aim was to examine phenotypic expression in colorectal neoplasia and to elucidate changes in such expression through the adenoma-carcinoma sequence.

METHODS AND RESULTS

We examined the expression of various proteins immunohistochemically in 111 flat [non-polypoid growth (NPG)] colorectal neoplasms, categorized into 28 low-grade (NPG-LGN), 44 high-grades (NPG-HGN) and 39 cases of invasive neoplasia (NPG-IN), as well as in 96 polypoid [polypoid growth (PG)] neoplasms, categorized into 26 PG-LGN, 39 PG-HGN and 31 PG-IN according to the Vienna classification. CD10 was more frequently expressed in NPG than in PG neoplasia. MUC2 and MUC5AC were more frequently expressed in PG than in NPG neoplasias. Nuclear beta-catenin was more frequently expressed in NPG-LGN than in PG-LGN. No difference in p53 expression was found between NPG and PG neoplasia.

CONCLUSIONS

From the viewpoint of the expression of CD10 and beta-catenin, it would appear that NPG-LGN differs significantly from PG-LGN, thereby indicating that NPG-LGN is a precursor of CD10+ carcinoma. It is important to ensure that NPG neoplasia is not overlooked if cases of CD10+ carcinoma are to be detected at an early stage.

CD10 Expression in Urothelial Bladder Carcinomas: A Pilot Study

OBJECTIVES

The aims of this study were to investigate the expression of CD10 in normal bladder tissue and urothelial bladder carcinomas and to clarify its association with histopathological variables.

MATERIALS AND METHODS

A total of 79 urothelial bladder carcinomas were selected from routine archival material. All cases were reevaluated histopathologically and graded according to the World Health Organization (WHO) 1973, WHO/ISUP 1998, and WHO 1999 systems. The TNM system was used for their pathological staging. CD10 immunohistochemical staining was performed in selected slides.

RESULTS

Tumoral cases consisted of 74 men (93.7%) and 5 women (6.3%). According to the pathological stage, 25 (31.6%), 33 (41.8%), and 21 (26.6%) cases had pTa, pT1, and pT2-3 carcinomas, respectively. 34 of 79 (43%) urothelial carcinomas and only 1 of 11 (9.1%) nontumoral cases showed positive CD10 immunostaining. It was a cytoplasmic diffuse or granular immunostaining pattern both in nontumoral and tumoral urothelia. There was no statistically significant difference between tumoral and nontumoral cases with respect to CD10 reactivity (p = 0.051), but there was a trend toward significance. In urothelial tumors, there was a significant inverse correlation between pathological stages and CD10 immunoreactivity (p = 0.036, r = -0,237). There was also a statistically significant difference between pTa and pT2-3 urothelial tumors in relation to the CD10 expression (p = 0.034). No association was detected between CD10 expression and grades according to all systems used (p > 0.05).

CONCLUSIONS

According to our findings, the CD10 expression in noninvasive carcinomas showed a higher level than that in invasive carcinomas, and it is inversely correlated with the pathological stage. CD10 may play an important role in the progression of urothelial bladder carcinomas, and downregulation probably facilitates invasion, especially muscle invasion.

Villous adenocarcinoma of the colon and rectum: a clinicopathologic study of 36 cases

Some colorectal adenocarcinomas show villous architecture with morphologic similarities to tubulovillous or villous adenomas. We reviewed 420 consecutive colorectal adenocarcinoma resection specimens and found that 95 tumors (23%) showed areas of villous architecture. Thirty-six tumors (8.6%) in 35 patients showed more than 50% villous architecture and were designated villous adenocarcinomas. Only 42% of the villous adenocarcinomas showed severe atypia and only 44% of the available pre-resection biopsies of these tumors were diagnosed as adenocarcinoma. Epithelial islands in desmoplastic stroma (EIDS) may be helpful in the diagnosis of these tumors. EIDS were found in 97% of the resection specimens for villous adenocarcinomas and none of 62 resection specimens for tubulovillous or villous adenomas. The presence of EIDS showed a 67% sensitivity, 100% specificity, and 100% predictive value in the diagnosis of villous adenocarcinoma in a blinded review of villous tumors. On review of the pre-resection biopsies of villous adenocarcinoma without a final diagnosis of adenocarcinoma, 40% showed EIDS. Clinical follow-up of the 35 patients with villous adenocarcinoma showed that only one died of colorectal adenocarcinoma (median follow-up, 46 months). This sole patient dying of colorectal adenocarcinoma showed a synchronous advanced stage of nonvillous adenocarcinoma at the time of diagnosis. Villous adenocarcinoma is a diagnostically challenging subset of colorectal adenocarcinoma, which appears to be associated with a favorable prognosis. Classifying these tumors as a special type of colorectal cancer may facilitate the development of diagnostic adjuncts and optimal treatment protocols.