Jari Sundström

Prognosis of patients treated for intracranial metastases with whole-brain irradiation

Seventy-five patients with brain metastases from solid tumours were treated with whole-brain irradiation at our institution between 1990 and 1993. The primary cancers included 35 cases of lung cancer, 19 cases of breast cancer, nine cases of renal-cell cancer, six cases of melanoma and six cases of other primary sites. In each case the total dose to the whole brain was at least 25 gray (Gy). The primary site, age, performance status, number of brain metastases and the presence of extracranial disease were studied as prognostic factors for survival. The median survival for the whole population was 4 months (range 1-62 months). The patients with the brain as the only metastatic site had significantly better survival (P = 0.019) than those with both intracranial and extracranial metastatic sites. Poor performance status at the time of diagnosis of brain metastases was also related to short survival (P = 0.001). None of the other studied variables had prognostic significance. Four of the 75 patients with primary tumour sites in the breast (two patients) and the kidney (two patients) survived for more than 2 years. In general, patients with breast cancer had better survival than patients with other primary cancers. Our study confirms the generally poor prognosis of cancer with brain metastases, although individual patients may survive several years after whole-brain irradiation. Approximately two-thirds of the patients experienced a relief in symptoms allowing a reduction in the dose of corticosteroid medication, which clearly supports the use of whole-brain radiotherapy as a palliative treatment.

Expression of carbonic anhydrase IX suggests poor outcome in rectal cancer

The aim of the study is to assess the value of carbonic anhydrase isozyme IX (CA IX) expression as a predictor of disease-free survival (DFS) and disease-specific survival (DSS) in rectal cancer treated by preoperative radio- or chemoradiotherapy or surgery only. Archival tumour samples from 166 patients were analysed for CA IX expression by three different evaluations: positive/negative, proportion of positivity and staining intensity. The results of immunohistochemical analysis were confirmed by demonstrating CA IX protein in western blotting analysis. Forty-four percent of the operative samples were CA IX positive, of these 34% had weak and 66% moderate/strong staining intensity. In univariate survival analysis, intensity of CA IX expression was a predictor of DFS (P=0.003) and DSS (P=0.034), both being markedly longer in tumours with negative or weakly positive staining. In multivariate Cox model, number of metastatic lymph nodes and CA IX intensity were the only independent predictors of DFS. Carbonic anhydrase isozyme IX intensity was the only independent predictor of DSS, with HR=9.2 for dying of disease with moderate-intense CA IX expression as compared with CA IX-negative/weak cases. Negative/weak CA IX staining intensity is an independent predictor of longer DFS and DSS in rectal cancer.

Type and location of tumor‐infiltrating macrophages and lymphatic vessels predict survival of colorectal cancer patients

The type of tumor‐infiltrating macrophages may be decisive in tumor immunity, lymphangiogenesis and in the clinical outcome of cancer. Here, we elucidated the prognostic significance of lymphatic vessels, different types of macrophages and the balance between different macrophage types in colorectal cancer. We analyzed the impact of density, type and location of macrophages on the clinical behavior of 159 primary colorectal carcinomas using CD68 as a pan‐macrophage marker and CLEVER‐1/Stabilin‐1 as a marker for regulatory/suppressive macrophages. Podoplanin was used as a pan‐lymphatic vessel marker. A high number of CLEVER‐1/Stabilin‐1+ peritumoral macrophages positively correlated with survival (p = 0.04). However, in more advanced disease (Stage IV), the patients with a high number of peritumoral or intratumoral CLEVER‐1/Stabilin‐1+ macrophages had a shorter disease‐specific survival (p = 0.05, and p = 0.008, respectively). Moreover, a low number of suppressive intratumoral CLEVER‐1/Stabilin‐1+ macrophages among high numbers of CD68+ macrophages correlated with a low number of distant recurrences (p = 0.01) and to fewer disease relapses exclusively in the liver as well (p = 0.006). A high number of intratumoral lymphatics correlated with poor survival (p = 0.03). The results of this work suggest that the type of macrophages, number of lymphatic vessels and their location contribute to the clinical behavior of colorectal cancer in a disease stage‐specific manner.

MicroRNA profiling differentiates colorectal cancer according to KRAS status

Recent studies have shown the important role of microRNAs (miRNAs) in a variety of biological processes, and in its ability to distinguish tumors according to their prognostic and predictive properties. To identify miRNA signatures associated with colorectal carcinoma (CRC) and with KRAS status, we studied, using Agilents miRNA microarrays, miRNA expression in primary tumors from 55 metastatic CRC patients, including 15 with mutant and 40 with wild‐type KRAS. Comparing these with normal colon tissue, we identified 49 miRNAs—including 19 novel miRNAs—significantly deregulated in tumor tissue. The presence of the KRAS mutation was associated with up‐regulation of miR‐127‐3p, miR‐92a, and miR‐486‐3p and down‐regulation of miR‐378. Increased expression of miR‐127‐3p and miR‐92a in KRAS mutant tumors was significantly confirmed by quantitative reverse transcriptase polymerase chain reaction (qRT‐PCR) (P < 0.05). We identified some predicted target genes of differentially expressed miRNAs between mutated and wild‐type KRAS, such as RSG3 and TOB1, which are involved in apoptosis and proliferation. Target prediction and pathway analysis suggest a possible role for deregulated miRNAs in nicotinamide adenine dinucleotide phosphate (NADPH) regeneration and G protein‐coupled receptor signaling pathways.

EGFR gene copy number assessment from areas with highest EGFR expression predicts response to anti-EGFR therapy in colorectal cancer

Background:Only 40–70% of metastatic colorectal cancers (mCRCs) with wild-type (WT) KRAS oncogene respond to anti-epidermal growth factor receptor (anti-EGFR) antibody treatment. EGFR amplification has been suggested as an additional marker to predict the response. However, improved methods for bringing the EGFR analysis into routine laboratory are needed.Methods:The material consisted of 80 patients with mCRC, 54 of them receiving anti-EGFR therapy. EGFR gene copy number (GCN) was analysed by automated silver in situ hybridisation (SISH). Immunohistochemical EGFR protein analysis was used to guide SISH assessment.Results:Clinical benefit was seen in 73% of high (⩾4.0) EGFR GCN patients, in comparison with 59% of KRAS WT patients. Only 20% of low EGFR GCN patients responded to therapy. A high EGFR GCN number associated with longer progression-free survival (P<0.0001) and overall survival (P=0.004). Together with KRAS analysis, EGFR GCN identified the responsive patients to anti-EGFR therapy more accurately than either test alone. The clinical benefit rate of KRAS WT/high EGFR GCN tumours was 82%.Conclusion:Our results show that automated EGFR SISH, in combination with KRAS mutation analysis, can be a useful and easily applicable technique in routine diagnostic practise for selecting patients for anti-EGFR therapy.

MicroRNA profiling predicts survival in anti-EGFR treated chemorefractory metastatic colorectal cancer patients with wild-type KRAS and BRAF

Anti-EGFR monoclonal antibodies (anti-EGFRmAb) serve in the treatment of metastatic colorectal cancer (mCRC), but patients with a mutation in KRAS/BRAF and nearly one-half of those without the mutation fail to respond. We performed microRNA (miRNA) analysis to find miRNAs predicting anti-EGFRmAb efficacy. Of the 99 mCRC patients, we studied differential miRNA expression by microarrays from primary tumors of 33 patients who had wild-type KRAS/BRAF and third- to sixth-line anti-EGFRmAb treatment, with/without irinotecan. We tested the association of each miRNA with overall survival (OS) by the Cox proportional hazards regression model. Significant miR-31* up-regulation and miR-592 down-regulation appeared in progressive disease versus disease control. miR-31* expression and down-regulation of its target genes SLC26A3 and ATN1 were verified by quantitative reverse transcriptase polymerase chain reaction. Clustering of patients based on miRNA expression revealed a significant difference in OS between patient clusters. Members of the let-7 family showed significant up-regulation in the patient cluster with poor OS. Additionally, miR-140-5p up-regulation and miR-1224-5p down-regulation were significantly associated with poor OS in both cluster analysis and the Cox proportional hazards regression model. In mCRC patients with wild-type KRAS/BRAF, miRNA profiling can efficiently predict the benefits of anti-EGFRmAb treatment. Larger series of patients are necessary for application of these miRNAs as predictive/prognostic markers.

Time course of female‐to‐male sex reversal in 38,XX fetal and postnatal pigs

In an attempt to understand the etiology of intersexuality in pigs, we thoroughly analyzed the gonads of 38,XX (SRY negative) female to male sex‐reversed animals at different developmental stages: during fetal life [50 and 70 days postcoitum (dpc)], just after birth [35 days postpartum (dpp)] and during adulthood. For each animal studied, we performed parallel histological and ultrastructural analyses on one gonad and RT‐PCR analysis on the other gonad in order to define the expression profiles of sexually regulated genes: SOX9, 3β‐HSD, P450 aromatase, AMH, FOXL2, and Wnt4. Light and electron microscopic examination showed that testicular cords differentiated in XX sex‐reversed gonads but were hypoplastic. Although the testicular cords contained gonia at the fetal stages, the germ cells had all died through apoptosis within a few weeks after birth. Ultrastructurally normal Leydig cells also differentiated, but later, and enclosed whorl‐like residual bodies. At the fetal stages, three of the six genes studied in the intersex gonads presented, as early as 50 dpc, a modified expression profile corresponding to an elevated expression of SOX9 and the beginning of AMH and P450 aromatase gene transcription. In addition to genes involved in the testicular pathway, the same gonads expressed FOXL2, an ovarian‐specific factor. The ovaries of true hermaphrodites were ineffective in ensuring correct folliculogenesis and presented abnormal expression profiles of ovarian specific genes after birth. These results indicate that the genes involved in this pathology act very early during gonadogenesis and affect the ovary‐differentiating pathway with variable expressivity from ovarian germ cell depletion through to trans‐differentiation into testicular structures.

Proliferation marker securin identifies favourable outcome in invasive ductal breast cancer

We introduce a new proliferation marker, securin (pituitary tumour-transforming 1 (PTTG1)), analysed in invasive ductal breast carcinomas by cDNA microarrays and immunohistochemistry. In cDNA microarray of a total of 4000 probes of genes, securin was revealed with a significant change in expression among the several proliferation-related genes studied. The value of securin as a proliferation marker was verified immunohistochemically (n=44) in invasive ductal breast cancer. In follow-up analyses of the sample of patients, the prognostic value of securin was compared with the established markers of breast cancer proliferation, Ki-67 and mitotic activity index (MAI). Our results of a small sample of patients suggest that low securin expression identifies a distinct subgroup of more favourable outcome among patients with high Ki-67 immunoexpression or high MAI. In univariate analysis of Coxs regression, 10-unit increment of securin immunopositivity was associated with a 2.3-fold overall risk of death due to breast cancer and a 7.1-fold risk of death due to breast cancer in the sample of patients stratified according to the cutoff points of 10 and 20% of securin immunopositivity. We suggest that securin immunostaining is a promising and clinically applicable proliferation marker. The finding urges further prognostic studies with a large sample of patients.

mRNA differential display of gene expression in colonic carcinoma

We analyzed changes in gene expression in human colonic carcinoma by fluorescent mRNA differential display. RNA isolated from two samples of normal colon and four cases of colonic adenocarcinoma were amplified with a 15×32 set of primers resulting in 2880 cDNAs analyzed with an automated sequencer. Electrophoretic patterns implying constitutive gene expression as well as upregulated and downregulated expression in carcinomas were identified. Forty such cDNA fragments were purified by a novel fluorescent polyacrylamide gel electrophoresis (PAGE)‐based method and identified by cyclic sequencing. Most genes showing differential expression were upregulated in colonic carcinoma. Upregulated genes included those for various ribosomal and mitochondrial proteins, heat shock proteins, nucleolar RNA‐helicase and phosphoserine aminotransferase. Downregulated genes included histone H3.3. In conclusion, genes associated with vital cellular functions such as transcription, protein synthesis and mitochondrial metabolism were upregulated in colonic carcinoma. Fluorescent mRNA differential display can be applied to the identification of novel cancer‐related genes for diagnostic, prognostic and therapeutic purposes.

ALDH1 expression indicates chemotherapy resistance and poor outcome in node-negative rectal cancer

The cancer stem cell marker aldehyde dehydrogenase 1 (ALDH1) associates with treatment resistance and adverse outcome in several human cancers. We studied ALDH1 expression in rectal cancer, with special emphasis on its association with treatment response and disease outcome. Immunohistochemical staining for ALDH1 was conducted for 64 biopsies and 209 operative samples from rectal cancer patients treated with short- (n = 89) or long-course (n = 46) (chemo)radiotherapy plus surgery, or with surgery only (n = 74). The staining results were compared to clinicopathological variables, tumor regression grade (TRG) and disease outcome. Nuclear β-catenin expression pattern was analyzed from 197 operative samples. Positive ALDH1 expression was present in 149 operative samples (71%), correlating with deficient nuclear β-catenin regulation (P = .018). In a pairwise comparison of respective biopsy and operative samples, ALDH1 expression remained stable or increased after preoperative (chemo)radiotherapy in most of the cases, while it decreased in few cases only (P = .02 for positive/negative category; P <.001 for intensity). ALDH1 expression did not, however, relate to tumor regression grade. In node-negative rectal cancer, ALDH1 expression was an independent predictor of short disease-free and disease-specific survival (P = .044; P = .049), specifically among patients treated with adjuvant chemotherapy. We conclude that ALDH1 associates with deregulated β-catenin signaling, supporting the role of ALDH1 in rectal cancer stemness. ALDH1 expression relates to poor outcome in early stage rectal cancer, a group where new prognostic tools are particularly needed, and may indicate chemo- and radioresistance.