Loss of αII and βIII Spectrin Isoforms in Body Fluids is Associated with Metastasis

Abstract

BackgroundSpectrins are the principal skeletal proteins involved in cellular adhesion, migration, and signal transduction, and have been shown to be associated with integrate structure and function in complex tissue of all multi cellular organisms. The present study investigates the role of spectrins in metastasis. MethodsThree categories of samples were studied. First, spectrin expression patterns were examined in 66 normal, benign and malignant samples. Second, 188 primary tumor cases, including 69 counts of metastasis, were studied. Finally 29 cases of body fluid metastasis without available primary tumor samples were studied. Expression of spectrin isoforms αII, βI, βII, and βIII were studied by immunohistochemistry in primary tumors (188 cases) with lymph node, remote organ, and body fluid metastasis; the 26 cases of malignant body fluids were paired with their corresponding primary tumors and analyzed. ResultsIn this paper we focus on the expression of αII and βIII isoforms. We found an aberrant loss of αII mainly in breast invasive ductal carcinoma, among other cancers. Positive body fluids had markedly reduced αII and βIII expression, (P<0.0009, P<0.0001 respectively). βII remained present in all the primary tumors and cytology samples. No difference was identified in lymph node or remote organ metastasis. ConclusionWe posit based on the established role of spectrins in various forms of cancer and in cell structure and adhesion that spectrins play an important role in maintaining tissue structure, with aberrant expression associated with body fluid metastasis. Subsequently, a panel of 188 cases of primary carcinoma was selected for analysis. Cases included colon (N=77), stomach (N=3), breast (N=9), endometrium carcinoma (N=3), ovary carcinoma (N=3), lung carcinoma (N=91, adenocarcinoma N=76 and squamous cell carcinoma N=15), and thyroid (N=2). 69 counts of metastasis were included within this cohort of 188 carcinomas, as follows: regional positive lymph nodes (N=33) from colon and breast; remote organ metastasis (N=10) from colon, thyroid, and breast, to lung and liver; and malignant body fluids (N=26), primarily from the colon, stomach, liver, breast, uterine endometrium, ovary, and lung. These 26 cases of malignant body fluids were paired with their corresponding primary tumors and analyzed. Some of these 69 metastatic samples represented single patients with multiple forms of metastasis; thus, this count of 69 metastasis samples does not equal 69 individual cases, as one case can have more than one metastasis. Keywords Tumor microarraysFor larger tissues, tumor microarrays were constructed from formalin-fixed, paraffin-embedded samples using a manual tissue arrayer (Chemicon International Temecula, CA). To ensure adequate sampling, each case was represented in triplicates using 1.0mm cores. For smaller biopsy samples, histologic contiguous sections were individually prepared. The immunohistochemical staining conditions for spectrin isoforms αI, αII, βI, βII and βIII are the same as previousl...