Right atrial cardiac myxoma with malignant transformation to undifferentiated sarcoma: A case report.

Generally, sarcomas arising from benign soft tissue are rare. Cardiac myxoma (CM) is a benign tumor, and few reports have described its malignant transformation. Herein, we documented a case of an 89-year-old man with prostate cancer and a 5-year history of a right atrium tumor without Carney complex. The tumor was resected surgically and had a myxomatous or gelatinous appearance. Microscopically, the tumor had two components: a sarcomatous area and myxomatous area. In the myxomatous area, typical myxoma cells were demonstrable and were strongly immunoreactive for immunohistochemistry (IHC) of calretinin. In the sarcomatous area, the epithelioid- to spindle-shaped cells with prominent atypia proliferated densely. The IHC profile of cells in the sarcomatous area was different from that of cells in the myxomatous area; MDM2-positive cells were found only in the sarcomatous area. Especially, the Ki-67 index and number of p53-positive cells in the sarcomatous area were higher than those in the myxomatous area. The transition of the two components was seamless. Thus, we made a diagnosis of CM with malignant transformation corresponding to undifferentiated pleomorphic sarcomas. This case suggests that CM may transform into sarcoma, albeit rarely.

The relationship between tumor immunity and the cGAS-STING pathway in breast cancer: An immunohistochemical study.

Breast cancer (BC) is classified into four major histological subtypes, namely luminal A, luminal B, HER2, and basal-like, and its treatment is based on these subtypes. The use of immune checkpoint inhibitors against BC depends on the expression of PD-1/PD-L1. Another tumor immune system-the cGAS-STING pathway-is a potential target for cancer immunotherapy. However, the status of the cGAS-STING pathway in BC has not been fully established. Therefore, we investigated the expression status of the cGAS-STING pathway and immune-related proteins in BC. We classified 111 BCs into six groups-29 hormone receptor-positive carcinomas, 12 HER2+ carcinomas (HER2), 8 luminal-HER2 carcinomas, 26 triple-negative breast carcinomas (TNBCs), 21 lobular carcinomas (LC), and 15 carcinomas with apocrine differentiation (CAD)-and investigated the relationship between BC and tumor immunity via the cGAS-STING pathway using histopathological and immunohistochemical methods. Expression of cGAS was high in CADs (100%) and low in TNBCs (35%); STING-positive lymphocytes were high in TNBC (85%, P = 0.0054). Expression of pSTAT3 was significantly high in patients with TNBC (≥10%, 88%). The proportion of PD-L1-positive tumor cells was higher in TNBCs (54%) than in other BCs (30%). SRGN expression was significantly higher in the TNBC group than in the other BC groups (58%). Tumor immune responses may differ among tumor subtypes. The cGAS-STING pathway may be functional in TNBC and CAD but not in LC. Therefore, targeting the cGAS-STING pathway might be useful in BC, particularly TNBC and CAD.

Clinical characteristics, proteins, and genes related to interstitial pneumonia-associated squamous cell carcinoma of the lungs.

Squamous cell carcinoma (SCC) is a common histological type of lung carcinoma that is associated with interstitial pneumonia (IP). We hypothesized that identifying specific genetic alterations or molecular markers of SCC with IP may aid the development of novel therapeutic strategies for the same. Therefore, in the present study, we aimed to identify tumorigenic genetic alterations and molecular markers in cases of SCC with IP. We included 28 lung SCC cases (14 cases with IP and 14 cases without IP). We performed immunohistochemistry for STAT3, STAT5, and TLE1, and next-generation sequencing was performed using an iSeq 100 system. The panel used in this study targeted 50 cancer-associated genes. Immunohistochemically, the rate of TLE1 positivity was higher in the SCC without IP group (93 %) than in the SCC with IP group (29 %), while that of STAT5 was higher in the SCC with IP group (79 %) than in the SCC without IP group (14 %). STAT3 expression was high in both the groups (SCC with IP, 64 %; SCC without IP, 71 %). Eighteen genes were mutated in more than six samples, and FBXW7 mutation was mainly observed in the SCC with IP group (p < 0.01). Mechanisms underlying tumorigenesis in SCC with IP included STAT5 activation via inflammation, while that in SCC without IP included squamous TLE1-mediated metaplasia. These findings are based on smoking-induced STAT3 activation; therefore, patients with IP who smoke are more likely to have progressive SCC. We also found that FBXW7 mutations may be associated with SCC with IP and keratinization. ERBB4 and KDR mutations were observed in both with or without IP, and these genes may be tumor-related genes in SCC. These molecular markers may help determine the prognoses of patients with SCC with IP and direct the development of treatment approaches.

Alpha-fetoprotein producing endometrioid carcinoma arising in an adenomyoma of the uterus.

We report a case of alpha-fetoprotein-producing endometrioid carcinoma (AFP-EC) that originated within an adenomyoma of the uterine corpus. A 76-year-old Japanese woman was incidentally discovered to have a uterine tumor along with multiple lung nodules. Upon surgical removal of the uterus, it was revealed that the tumor was situated within the adenomyoma. The tumor exhibited microfollicular structures and solid growth patterns, with hyaline globules, clear cell glands, and primitive tumor cells. Immunohistochemical analysis indicated the presence of germ cell markers, including AFP, SALL4, and glypican3, leading to final diagnosis of AFP-EC. Histopathologically, AFP-ECs exhibit characteristics similar to those of AFP-producing neoplasms in other organs. Furthermore, a nomenclature issue arises when distinguishing AFP-ECs from yolk sac tumors of the endometrium in older patients due to their shared features. The concept of retrodifferentiation or neometaplasia suggests that "endometrioid carcinoma with yolk sac tumor differentiation" or "endometrioid carcinoma with a primitive phenotype" may serve as more fitting terms for the diverse spectrum of AFP-producing neoplasms in the endometrium. In conclusion, this case underscores the diagnostic challenges posed by AFP-ECs arising from adenomyomas and emphasizes the need for refining the nomenclature and classification of AFP-producing neoplasms within the endometrium.

Immunohistochemical staining of versican as a potential marker for predicting lymph node metastasis in gastric cancer.

Gastric cancer is one of the most common cancers and has a high mortality rate. Lymph node metastasis is a key determinant of prognosis, and an essential mechanism involved in metastasis is the epithelial-mesenchymal transition. In this study, we aimed to assess the diagnostic role of versican (VCAN), a molecule participating in the epithelial-mesenchymal transition, on the detection of metastatic cancer. The expression of VCAN was evaluated using immunohistochemistry, and its biological activity was examined using gastric cancer cell lines. In patients with lymph node metastasis, VCAN expression was more prominent at primary tumor sites. In addition, VCAN was found to promote cell migration in vitro, thus potentially facilitating the distribution of metastases. Overall, increased expression of VCAN at the primary site may signify the development of metastases in lymph nodes because this protein is recognized as contributing to the migration of cancer cells into lymph nodes.

Clinicopathological correlations of endometrioid and clear cell carcinomas in the uterus and ovary.

Endometrioid carcinoma (EC) and clear cell carcinoma (CC) are associated with endometrial tissue hyperplasia and endometriosis, and they occur in the endometrium and ovaries. However, detailed differences between these tumors based on immunostaining are unclear; therefore, in this study, we aimed to analyze the clinicopathological correlations between these tumors using immunostaining and to develop new treatments based on histological subtypes. Immunohistochemistry was used to investigate differentially expressed hypoxia-associated molecules (hypoxia-inducible factor-1 subunit alpha [HIF-1α], forkhead box O1, prostate-specific membrane antigen, signal transducer and activator of transcription 3 [STAT3], hepatocyte nuclear factor 1ß [HNF-1ß], aquaporin-3, and vimentin [VIM]) between these carcinomas because of the reported association between CC and ischemia. Immunostaining and clinicopathological data from 70 patients (21 uterine endometrioid carcinomas [UECs], 9 uterine cell carcinomas, 20 ovarian endometrioid carcinomas [OECs], and 20 ovarian cell carcinomas [OCCs]) were compared. HIF-1α and prostate-specific membrane antigen expression levels were higher in UEC and OCC than in uterine cell carcinomas and OEC. STAT3 was slightly overexpressed in UEC. Additionally, forkhead box O1 expression was either absent or significantly attenuated in all ECs. VIM and AQ3 were highly expressed in UEC, whereas HNF-1ß expression was higher in OCC. UEC, OEC, and OCC were more common in the uterine fundus, left ovary, and right ovary, respectively. Ovarian endometriosis was strongly associated with EC. Our findings suggest that UEC and OCC share a carcinogenic pathway that involves HIF-1α induction under hypoxic conditions via STAT3 expression, resulting in angiogenesis. Furthermore, the anatomical position of carcinomas may contribute to their carcinogenesis. Finally, aquaporin-3 and VIM demonstrate strong potential as biomarkers for UEC, whereas HNF-1ß expression is a crucial factor in CC development. These differences in tumor site and histological subtypes shown in this study will lead to the establishment of treatment based on histological and immunohistological classification.

Uncommon case of cytopathological features of sialadenoma papilliferum.

Sialadenoma papilliferum, a benign and rare salivary gland neoplasm, accounts for 0.4%-1.2% of all salivary gland tumors and occurs primarily in minor salivary glands of the oral cavity. Here, we report a case of sialadenoma papilliferum and its associated cytological findings. A papillary tumor was incidentally detected on the palate of an 86-year-old Japanese man. Conventional oral exfoliative cytology was performed; the cytology smear exhibited epithelial clusters composed of atypical epithelial cells with a high nuclear/cytoplasm ratio and arranged in sheet or small papillary-like projections. Cytoplasmic vacuoles were also observed in the papillae. It was difficult to make a definitive diagnosis due to the presence of uncommon cytological features. The excisional biopsy specimen revealed histological features characteristic of sialadenoma papilliferum. Mutational analysis detected BRAFV600E mutation, which confirmed the diagnosis of sialadenoma papilliferum. To the best of our knowledge, no prior cytomorphological evaluations of sialadenoma papilliferum have been reported in detail. Oral exfoliative cytology specimens from salivary gland tumors can demonstrate uncommon cytomorphological features. A differential diagnosis of sialadenoma papilliferum can be based on the observation of mildly atypical epithelial cells that form small papillary-like structures.

Histopathological Aspects of the Prognostic Factors for Salivary Gland Cancers.

Salivary gland cancers (SGCs) are diagnosed using histopathological examination, which significantly contributes to their progression, including lymph node/distant metastasis or local recurrence. In the current World Health Organization (WHO) Classification of Head and Neck Tumors: Salivary Glands (5th edition), malignant and benign epithelial tumors are classified into 21 and 15 tumor types, respectively. All malignant tumors have the potential for lymph node/distant metastasis or local recurrence. In particular, mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), salivary duct carcinoma, salivary carcinoma, not otherwise specified (NOS, formerly known as adenocarcinoma, NOS), myoepithelial carcinoma, epithelial-myoepithelial carcinoma, and carcinoma ex pleomorphic adenoma (PA) are relatively prevalent. High-grade transformation is an important aspect of tumor progression in SGCs. MEC, AdCC, salivary carcinoma, and NOS have a distinct grading system; however, a universal histological grading system for SGCs has not yet been recommended. Conversely, PA is considered benign; nonetheless, it should be cautiously treated to avoid the development of metastasizing/recurrent PA. The aim of this review is to describe the current histopathological aspects of the prognostic factors for SGCs and discuss the genes or molecules used as diagnostic tools that might have treatment target potential in the future.

CD8/PD-L1 immunohistochemical reactivity and gene alterations in cutaneous squamous cell carcinoma.

In recent years, several immune checkpoint inhibitors targeting programmed death-ligand 1 (PD-L1) or PD-1 have been developed for cancer therapy. The genetic background of tumors and factors that influence PD-L1 expression in tumor tissues are not yet elucidated in cutaneous squamous cell carcinoma (cSCC). CD8-positive tumor-infiltrating lymphocytes (TILs) are known to be related to tumor immunity. Here, we aimed to study the relationship between CD8/PD-L1 immunohistochemical reactivity and gene alterations in cSCC. Tumorigenic genes were examined to identify gene alterations using next-generation sequencing (NGS). We collected 27 cSCC tissue samples (from 13 metastatic and 14 non-metastatic patients at primary diagnosis). We performed immunohistochemical staining for CD8 and PD-L1, and NGS using a commercially available sequencing panel (Illumina Cancer Hotspot Panel V2) that targets 50 cancer-associated genes. Immunohistochemically, CD8-positive TILs showed a high positive score in cSCC without metastasis; in these cases, cSCC occurred predominantly in sun-exposed areas, the tumor size was smaller, and the total gene variation numbers were notably low. The tumor depth, PD-L1 positivity, and gene variation number with or without tumor metastasis were not related, but the gene variation number tended to be higher in cSCCs arising in non-sun-exposed areas. Tumor metastasis was more common in cSCC arising in non-sun-exposed areas, which decreased the number of TILs or CD8-positive cells. From a genetic perspective, the total gene alterations were higher in cSCC with metastasis. Among them, ERBB4 and NPM1 are presumably involved in cSCC tumorigenesis; in addition, GNAQ, GNAS, JAK2, NRAS, IDH2, and CTNNB1 may be related to tumor metastasis. These results provide information on potential genes that can be targeted for cSCC therapy and on immune checkpoint inhibitors that may be used for cSCC therapy.

Micronodular Thymic Carcinoma with Lymphoid Stroma: A Case Report.

Background. Micronodular thymic carcinoma (MTC) with lymphoid hyperplasia is believed to be the malignant counterpart of micronodular thymoma (MT) with lymphoid hyperplasia. Since MT and MTC share a similar morphology, MTC is considered a malignant form of MT; there have been a few malignant transformations from MT to MTC. We report a case of MTC with lymphoid hyperplasia. Case presentation. A 53-year-old woman presented with an incidental tumor on a chest X-ray. The resected tumor consisted of nodular epithelial nests and lymphoid tissue within a surrounding germinal center. Some epithelial nests showed apparent malignant morphology. Atypical epithelial cells with large vesicular nuclei formed nests, some of which showed comedo necrosis. These cells showed transition continuously to low-grade type B thymoma-like cells, demonstrating cord-like arrangements. Carcinomatous elements, expressed GLUT1, CD5, KIT, and BCL2; conversely, low-grade nests displayed attenuated expression of these markers. GTF2I point mutation and Langerhans/dendritic cells, which are indicators of favorable thymoma prognosis, were not detected. Due to pleural metastasis, the patient was treated with lenvatinib 27 months postoperatively. Conclusions. This is the first report of a partially low-grade, GTF2I-negative MTC. Histological and genetic findings might be predictive of tumor prognosis.

Immunohistochemical and molecular analysis of an α-fetoprotein-producing cervical adenocarcinoma with clear cell morphology.

Adenocarcinomas with clear cell morphology may be associated with elevated serum alpha-fetoprotein levels in various organs. We report the case of an alpha-fetoprotein-producing cervical adenocarcinoma with clear cell morphology and compare it immunohistochemically, molecularly, and virologically with cervical clear cell carcinoma, gastric-type mucinous carcinoma, and ovarian clear cell carcinoma. A 51-year-old Japanese woman was initially diagnosed with cervical clear cell carcinoma. The tumor was resistant to standard surgery, radiotherapy, and chemotherapy. Serum carcinoembryonic antigen and alpha-fetoprotein were elevated. The tumor was immunohistochemically positive for alpha-fetoprotein, human chorionic gonadotropin, cytokeratin 20, spalt-like transcription factor 4, glypican 3, MUC6, and HIK1083. Gene panel testing revealed CCNE1 amplification, CDKN2A loss, and TP53 R282W. We compared the present case with 120 ovarian clear cell carcinoma cases using a tissue microarray. Only one case (0.8%) showed very limited immunohistochemical positivity for alpha-fetoprotein. Of the 54 cases in which serum carcinoembryonic antigen was measured, only one (1.9%) was elevated (19.9 ng/mL). We diagnosed the case as alpha-fetoprotein-producing cervical gastric-type mucinous carcinoma with enteroblastic differentiation. In conclusion, alpha-fetoprotein-producing cervical adenocarcinoma is a rare but aggressive tumor. Clinicians and pathologists should be aware of this unfamiliar tumor, its diagnostic clues, prognostic markers, and treatment strategies.

An autopsy case of recurrent pneumothorax and peliosis-like intrapulmonary hematoma with X-linked myotubular myopathy.

BACKGROUND: The typical non-muscle complications of long-surviving X-linked myotubular myopathy (XLMTM) include scoliosis, head deformity, macrocephaly, gastroesophageal reflux disease and peliosis hepatis. Recently, pulmonary blebs and recurrent pneumothorax have also been reported as uncommon complications, whereas no reports on autopsy cases have focused on lung lesions. CASE PRESENTATION: An 8-year-old boy with XLMTM presented recurrent pneumothorax requiring bleb resection and pleurodesis. He subsequently developed multiple pulmonary mass lesions. He died of hemorrhagic shock due to peliosis hepatis. Autopsy showed multiple peliosis-like hematomas in the blebs of the lung. The histopathological examination of the hematomas revealed pooled blood without a pathway to bronchus. No apparent increase in desmin- or α-smooth muscle actin (α-SMA)-positive cells, namely myofibroblasts, was observed around hematomas, suggesting that the mutation in the myotubularin gene was involved in the defective repair process in the liver and lung tissues. CONCLUSION: Recurrent pneumothorax should be considered as a non-muscle complication of XLMTM. Peliosis-like intrapulmonary hematoma may also be a critical complication caused by poor proliferation of myofibroblasts in the tissue repair process.

Immunohistochemical Reactivity of Prostate-Specific Membrane Antigen in Salivary Gland Tumors.

Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein that is overexpressed in the prostate gland and prostate cancer. PSMA has been recently used in positron emission tomography/computed tomography (PET/CT) imaging and targeted alpha-radiation therapy (TAT) for prostate cancer. Recently, the tubarial gland, a type of minor salivary gland that is described as a new organ situated in the pharynx, is reported to express PMSA. Here, we studied the expression of PSMA in common benign and malignant salivary gland tumors. We performed immunohistochemistry for PSMA in 55 salivary gland tumors comprising 10 pleomorphic adenomas, 10 Warthin tumors, 9 basal cell adenomas, 9 adenoid cystic carcinomas, 9 mucoepidermoid carcinomas, and 8 salivary duct carcinomas. PSMA was expressed in 97% of benign tumors and 77% of malignant tumors. Moreover, PSMA was expressed in 59% of normal salivary glands adjacent to the tumor. PSMA is relatively expressed in salivary gland tumors and salivary glands. Therefore, salivary gland neoplasm, and normal salivary gland, possibly demonstrate the accumulation of PSMA in PET/CT. Thus, we need to monitor the side effects in the salivary glands during TAT for prostate cancer.

Pulmonary wedge aspiration cytology for the rapid diagnosis of pulmonary tumor thrombotic microangiopathy: A case report.

Pulmonary tumor thrombotic microangiopathy (PTTM) is a cancer-related pulmonary complication characterized by rapid progression of dyspnea and pulmonary hypertension, occasionally causing sudden death. Given the condition of patients with dyspnea, lung biopsies are limited because of their invasiveness. A 72-year-old man presented with chronic atrial fibrillation and a high right heart load, as determined using ultrasonography. He had previously undergone resection of the left axillary skin secondary to extramammary Paget's disease (EMPD). Clinically, PTTM was suspected and pulmonary wedge aspiration cytology, collected from the pulmonary artery during catherization, was performed. Cytologically, the tumor demonstrated three-dimensional cell clusters with good cohesion and molding by the blood vessel lumen. Additionally, endothelial-like cells were observed at the periphery of the tumor clusters; fibrin was evident in the clusters. The tumor cells were large, round, and had high nuclear/cytoplasmic ratios. The nuclei demonstrated a variety of sizes and were irregularly shaped, with prominent nucleoli; cells undergoing mitosis were evident. The tumor cells were suspected of being poorly differentiated adenocarcinoma cells, consistent with PTTM. Two days after the aspiration cytology, the patient died and a pathological autopsy was performed. Histologically, the PTTM was determined to have caused the pulmonary hypertension and the primary PTTM site was apparently derived from the EMPD. For rapid diagnoses, an understanding of the tumor's cytological features is important and should contribute to early treatment intervention. Aspiration cytology, using pulmonary artery blood samples, during catherization is a useful tool for diagnosing PTTM.

A Case of Dendritic Cell Neurofibroma With Pseudorosettes.

Dendritic cell neurofibroma with pseudorosettes (DCNP) is a rare benign peripheral nerve sheath tumor. Till date, 34 cases of DCNP arising from various sites have been reported. Histopathologically, DCNP is known to present with characteristic pseudorosettes, in which a type II cell is surrounded by type I cells. In the present report, we discuss the rare case of a 63-year-old man diagnosed with DCNP on the left flank (size: approximately 10 mm). On microscopic examination of the resected lesion, we observed the characteristic pseudorosettes with centrally placed type I cells, which exhibited small, dark, slightly irregular oval nuclei with nuclear inclusions, surrounded by type II cells, which showed a large pale nucleus with a constriction, a small nucleolus, and mildly eosinophilic cytoplasm. The type II cells were positive for S-100, CD57, LAMP2, fascin, and factor XIIIa. Although previous reports have suggested that type II cells exhibit a dendritic form, our immunohistochemical analyses revealed that these cells were dermal interstitial dendritic cells.

Pulmonary tumor thrombotic microangiopathy associated with extramammary Paget's disease: An autopsy case report.

Pulmonary tumor thrombotic microangiopathy (PTTM) is histologically characterized by micro tumor cell embolism and intimal fibrocellular proliferation of pulmonary arteries or arterioles. We report a secondary case of PTTM associated with extramammary Paget's disease (EMPD). The patient was a 72-year-old man with exertional dyspnea. Clinical examinations found he had pulmonary hypertension and multiple osteolytic lesions of vertebra. Cytological analysis of pulmonary wedge artery sample detected malignant cells and he was dead before treatment was started. Multiple tumor embolisms (>17) were identified in pulmonary arteries or arterioles at autopsy, consistent with PTTM. Metastatic nodules were found in liver and lymph node. Furthermore, disseminated carcinomatosis of the bone marrow (DCBM) was seen. Immunostaining results pointed out that tumor cells possessed mammary gland phenotype. He had 4-years history of EMPD in the left axilla without recurrence, and immunohistochemistry results were the same as the autopsy specimen. Thus, we diagnosed the primary site of PTTM to be EMPD. Our case highlights the usefulness of the recent proposed classification of PTTM, potential association between PTTM and DCBM, and the necessity for long-term follow-up in EMPD. EMPD can rarely cause PTTM to manifest as a paraneoplastic syndrome.

A case of desmoplastic fibroma of bone with CTNNB1 point mutation.

Desmoplastic fibroma of bone (DFB), a bone tumor, is considered to be an osseous counterpart of desmoid-type fibromatosis (DF). Herein, we report a case of DFB with CTNNB1 point mutation. The 5-year-old male patient had complained of trismus and pain in the jaw. Magnetic resonance imaging revealed a mass in the left mandible. Radical treatment involved surgical resection. Microscopically, the lesion consisted of a bundle-like proliferation of uniform spindle-shaped cells with abundant collagenous stroma, which resembled DF. Immunohistochemical analysis revealed intranuclear accumulation of ß-catenin in the tumor cells. Based on clinical and histologic analysis, we diagnosed the patient as having DFB. We examined the CTNNB1 and APC sequence and found an A-to-G transition at codon 41 of CTNNB1; i.e., Thr was substituted by Ala. Our findings suggest that the dysregulation of Wnt/ß-catenin signaling pathway is related to the tumorigenesis of some cases of DFB. This hypothesis indicates that there are some cases of DFB in which nuclear positive expression of ß-catenin is useful for diagnosis.

Localized biphasic malignant peritoneal mesothelioma presenting as a rectal tumor.

An 84-year-old male presented with bloody stool. On digital rectal examination, a large and firm tumor was palpated in the anterior wall of the rectum at 2 cm from the anal verge. The colonoscopy revealed an ulcerated mass with smooth margins in the anterior wall of the rectum. Enhanced computed tomography showed a huge tumor in the pelvis, invading rectum, urinary bladder and the prostate, with signs of splenic and peritoneal metastases. Findings from an endoscopic biopsy and endoscopic ultrasound-guided fine needle aspiration suggested spindle cell carcinoma. We tentatively diagnosed as spindle cell carcinoma of the rectum and administered panitumumab as palliative chemotherapy. He eventually died at 4 months after the first visit to our institution. The autopsy findings resulted in the confirmed diagnosis as biphasic malignant peritoneal mesothelioma. There are only four previous reports on malignant peritoneal mesothelioma presenting as a colorectal tumor. Although rare, malignant peritoneal mesothelioma should be considered in differential diagnosis of colorectal tumors.