PLK (polo-like kinase), the human counterpart of polo in Drosophila melanogaster and of CDC5 in Saccharomyces cerevisiae, belongs to a family of serine/threonine kinases. It is intimately involved in spindle formation and chromosome segregation during mitosis. The purpose of this study was to determine whether PLK1 is overexpressed in primary colorectal cancer specimens as compared with normal colon mucosa and to assess its relation to other kinases as a potential new tumor marker. In the present study, immunohistochemical analyses were performed of PLK1 expression in 78 primary colorectal cancers as well as 15 normal colorectal specimens. Furthermore, we examined the relationship between other kinases, Aurora-A and Aurora-C, and PLK1 expression. In normal colon mucosa, some crypt cells showed weakly positive staining for PLK1 in 13 out of 15 cases, the remaining cases being negative. Elevated expression of PLK1 was observed in 57 (73.1%) of the colorectal cancers, statistically significant associations being evident with pT (primary tumor invasion) (P = = = =0.0006, Mann-Whitney U test), pN (regional lymph nodes) (P = = = =0.008, χ χ χ χ 2 test) and the Dukes' classification (P = = = =0.0005, MannWhitney U test). Mean proliferating cell nuclear antigen-labeling index was 52.3%, with a range of 24.1% to 77.3%. Values for lesions with high and low PLK1 expression were 54.7 ± ± ± ±10.3% (mean ± ± ± ±SD) and 45.9 ± ± ± ±11.9% (P = = = =0.002, Student's t test). PLK1 was significantly associated with Aurora-A, but PLK1 staining was more diffuse and extensive than for Aurora-A or Aurora-C. Interestingly, PLK1 overexpression was significantly associated with p53 accumulation in colorectal cancers. Our results suggest overexpression of PLK1 might be of pathogenic, prognostic and proliferative importance, so that this kinase might have potential as a new tumor marker for colorectal cancers. (Cancer Sci 2003; 94: 148-152)

Malignancies of the nasal cavity and paranasal sinuses account for 1% of all malignancies and 3% of malignancies of the upper aerodigestive tract. In the sinonasal tract, nearly half of all malignancies arise in the nasal cavity, whereas most of the remaining malignancies arise in the maxillary or ethmoid sinus. Squamous cell carcinoma is the most common histological subtype of malignant tumors occurring in this area, followed by other epithelial carcinomas, lymphomas, and malignant soft tissue tumors. Although many of these tumors present with nonspecific symptoms, each tumor exhibits characteristic imaging features. Although complex anatomy and various normal variants of the sinonasal tract cause difficulty in identifying the origin and extension of large sinonasal tumors, the invasion of vital structures such as the brain, optic nerves, and internal carotid artery affects patients’ prognosis. Thus, diagnostic imaging plays a key role in predicting the histological subtype and in evaluating a tumor extension into adjacent structures. This article describes the computed tomography and magnetic resonance imaging findings for malignant sinonasal tumors.

Computer algorithm analysis of equilibrium phase images was found to reflect the degree of fibrosis most accurately. MR image texture analysis performed using the computer algorithm was found to have a potential usefulness for the diagnosis of hepatic fibrosis.

SUMMARY:We present 4 cases of carcinoma ex pleomorphic adenoma of the parotid gland. In 3 of the 4 cases, diffusion-weighted and apparent diffusion coefficient (ADC) mapping images clearly revealed carcinoma as a hypercellular area with low ADC values and pleomorphic adenoma as a hypocellular area with high ADC values. Diffusion-weighted images demonstrated well complex tissue components in carcinoma ex pleomorphic adenoma, which may be useful for the diagnosis of this disease. P leomorphic adenoma is a common neoplasm that arises from the major salivary glands and infrequently undergoes malignant transformation. Malignant changes in pleomorphic adenoma have been associated with a long duration, tumor recurrence, radiation therapy, an advanced age, and tumor size. Because the incidence of malignancy is correlated with the duration of pleomorphic adenoma, the risk of developing malignancy is only about 1.5% for a duration of Ͻ5 years but increases to 9.5% for a duration of Ͼ15 years.1 Carcinoma ex pleomorphic adenoma is an infrequent aggressive malignancy that is believed to evolve from a pre-existing benign adenoma. It accounts for 3.6% (range, 0.9%-14%) of all salivary neoplasms and for 11.7% (range, 2.8%-42.4%) of salivary malignancies.2 Meanwhile, the imaging findings of carcinoma ex pleomorphic adenoma are often nonspecific and are not precisely differentiated from those of other benign and malignant salivary gland tumors. Here, we describe the imaging findings of 4 patients with carcinoma ex pleomorphic adenoma of the parotid gland and correlate these with pathologic findings. Furthermore, we discuss MR imaging diagnostic clues in carcinoma ex pleomorphic adenoma of the parotid gland. Case Reports MR ImagingMR imaging was performed by using a 1.5T MR imaging system (Intera Achieva 1.5T. Pulsar; Philips Medical Systems, Best, the Netherlands) with parallel imaging capability (referred to as sensitivity encoding). Axial diffusion-weighted (5000 -5100/70 -72 [TR/TE], 256 ϫ 256 matrix) images were obtained by using a single-shot spinecho echo-planar imaging sequence with a section thickness of 4 mm, without an intersection gap, in all patients. The sequence was executed with 2 values of motion-probing gradients (b ϭ 0 and 1000 s/mm 2 ). Case 1A 48-year-old woman felt a slowly enlarging right parotid gland for 5 years. The parotid mass was painless without facial nerve paralysis. T2-weighted images exhibited the 35 ϫ 25 mm mass in a well-demarcated area of heterogeneous intensity ( Fig 1A). Case 2A 76-year-old man had a painless mass in the right parotid gland for 50 years and had undergone surgical resection twice. The residual tumor had grown rapidly during the prior 6 months. The recurrent tumor was painless with facial nerve paralysis. T2-weighted images exhibited the 52 ϫ 47 mm mass as a well-demarcated area of heterogeneous intensity (Fig 2A). The anterior component showed mild high intensity, and the margins of the posterior component showed low intensity on T2-weighted images. Diffusion-weighted and ADC...

The purpose of our study was to evaluate the usefulness of diffusion-weighted imaging in predicting the responses to neoadjuvant therapy for head and neck squamous cell carcinomas. Diffusion-weighted, T2-weighted, and gadolinium-enhanced T1-weighted images were obtained from 28 patients with untreated head and neck squamous cell carcinomas with histological proof. A blinded radiologist evaluated the quantitative and qualitative signal intensities and apparent diffusion coefficients (ADCs) in the lesions on each sequence. All patients were treated by neoadjuvant therapies, and the post-therapeutic tumor regression rate was determined. Both the quantitative and qualitative signal intensities on diffusion-weighted images showed positive correlations (r = 0.367 and 0.412, p < .05), and the ADCs showed a weak, inversed correlation (r = -0.384, p < .05) with the tumor regression rates. Diffusion-weighted imaging including an assessment by ADCs may be able to predict tumor response to neoadjuvant therapy for head and neck squamous cell carcinomas.